[Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1.1: Type: text/plain, Size: 757 bytes --]

Hi,

some may recall the "micro-optimisation" thread I once started. Here is
now a simple approach to deal with the yet suboptimal mux-code
calculation in user-space. Code saving:

Before:
   text    data     bss     dec     hex filename
  18004     476       8   18488    4838 native/.libs/libnative.so
  27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so

After:
   text    data     bss     dec     hex filename
  17172     476       8   17656    44f8 native/.libs/libnative.so
  26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so

Of course, this also results in a few ops less being executed on each
Xenomai syscall invocation (not many cycles, though).

Tested without problems on x86 so far.

Jan

[-- Attachment #1.2: optimise-muxcode-calculation.patch --]
[-- Type: text/plain, Size: 7257 bytes --]

---
 include/asm-arm/syscall.h      |   25 +++++++++++++------------
 include/asm-blackfin/syscall.h |    4 +++-
 include/asm-i386/syscall.h     |    3 ++-
 include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
 include/asm-powerpc/syscall.h  |    3 ++-
 ksrc/nucleus/shadow.c          |    3 ++-
 6 files changed, 34 insertions(+), 27 deletions(-)

Index: xenomai/include/asm-arm/syscall.h
===================================================================
--- xenomai.orig/include/asm-arm/syscall.h
+++ xenomai/include/asm-arm/syscall.h
@@ -26,6 +26,7 @@
 #include <asm-generic/xenomai/syscall.h>
 
 #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
 
 #define XENO_ARM_SYSCALL        0x009F0042	/* carefully chosen... */
 
@@ -131,19 +132,19 @@ static inline int __xn_interrupted_p(str
 #define __sys1(x)	__sys2(x)
 
 #define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
-  ({								                    \
-        unsigned long __res;					        \
+  ({								\
+        unsigned long __res;					\
 	register unsigned long __res_r0 __asm__ ("r0");		\
-   	ASM_INDECL_##nr;					                \
-								                        \
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		    \
-	__asm__ __volatile__ (					            \
-"       swi " __sys1(XENO_ARM_SYSCALL)			        \
-		: "=r" (__res_r0)				                \
-		: ASM_INPUT_##nr				                \
-		: "memory");					                \
-   	__res = __res_r0;					                \
-   	(int) __res;						                \
+   	ASM_INDECL_##nr;					\
+								\
+	LOADARGS_##nr(__xn_mux_code_shft(id,op), args);		\
+	__asm__ __volatile__ (					\
+"       swi " __sys1(XENO_ARM_SYSCALL)				\
+		: "=r" (__res_r0)				\
+		: ASM_INPUT_##nr				\
+		: "memory");					\
+   	__res = __res_r0;					\
+   	(int) __res;						\
   })
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
Index: xenomai/include/asm-blackfin/syscall.h
===================================================================
--- xenomai.orig/include/asm-blackfin/syscall.h
+++ xenomai/include/asm-blackfin/syscall.h
@@ -27,6 +27,7 @@
    (i.e. negative syscall number in orig_p0 meaning "non-syscall
    entry"). */
 #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
 
 /* Local syscalls -- the braindamage thing about this arch is the
    absence of atomic ops usable from user-space; so we export what
@@ -213,7 +214,8 @@ static inline int __xn_interrupted_p(str
   __res;								\
 })
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)	__emit_syscall##nr(__xn_mux_code(id,op), ##args)
+#define XENOMAI_DO_SYSCALL(nr, id, op, args...) \
+    __emit_syscall##nr(__xn_mux_code_shft(id,op), ##args)
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
 #define XENOMAI_SYSCALL1(op,a1)             XENOMAI_DO_SYSCALL(1,0,op,a1)
Index: xenomai/include/asm-i386/syscall.h
===================================================================
--- xenomai.orig/include/asm-i386/syscall.h
+++ xenomai/include/asm-i386/syscall.h
@@ -23,6 +23,7 @@
 #include <asm-generic/xenomai/syscall.h>
 
 #define __xn_mux_code(id,op)  ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0x7fff))
 
 #ifdef __KERNEL__
 
@@ -167,7 +168,7 @@ asm (".L__X'%ebx = 1\n\t"
 
 #define XENOMAI_SKIN_MUX(nr, id, op, args...) \
   ({								      \
-    int muxcode = __xn_mux_code(id,op);                               \
+    int muxcode = __xn_mux_code_shft(id,op);			      \
     unsigned resultvar;						      \
     asm volatile (						      \
     LOADARGS_##nr						      \
Index: xenomai/include/asm-ia64/syscall.h
===================================================================
--- xenomai.orig/include/asm-ia64/syscall.h
+++ xenomai/include/asm-ia64/syscall.h
@@ -24,6 +24,7 @@
 #include <asm-generic/xenomai/syscall.h>
 
 #define __xn_mux_code(id,op)        ((op << 24)|(((id << 16) & 0xff0000UL)|(__xn_sys_mux & 0xffffUL)))
+#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffffUL))
 
 #ifdef __KERNEL__
 
@@ -151,17 +152,17 @@ static inline int __xn_interrupted_p(str
   /* Branch registers.  */						\
   "b6", "b7"
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...)                   \
-  ({                                                            \
-    register long _r15 asm ("r15") = (__xn_mux_code(id,op));    \
-    register long _retval asm ("r8");                           \
-    register long err asm ("r10");                              \
-    LOAD_ARGS_##nr (args);                                      \
-    __asm __volatile ("break %3;;\n\t"                          \
-                      : "=r" (_retval), "=r" (_r15), "=r" (err) \
-                      : "i" (__BREAK_SYSCALL), "1" (_r15)       \
-			ASM_ARGS_##nr                           \
-                      : "memory" ASM_CLOBBERS_##nr);            \
+#define XENOMAI_SKIN_MUX(nr, id, op, args...)				\
+  ({									\
+    register long _r15 asm ("r15") = (__xn_mux_code_shft(id,op));	\
+    register long _retval asm ("r8");					\
+    register long err asm ("r10");					\
+    LOAD_ARGS_##nr (args);						\
+    __asm __volatile ("break %3;;\n\t"					\
+		      : "=r" (_retval), "=r" (_r15), "=r" (err)		\
+		      : "i" (__BREAK_SYSCALL), "1" (_r15)		\
+			ASM_ARGS_##nr					\
+		      : "memory" ASM_CLOBBERS_##nr);			\
     err < 0 ? -_retval : _retval; })
 
 #define XENOMAI_SYS_MUX(nr, op, args...) XENOMAI_SKIN_MUX(nr, 0, op , ##args)
Index: xenomai/include/asm-powerpc/syscall.h
===================================================================
--- xenomai.orig/include/asm-powerpc/syscall.h
+++ xenomai/include/asm-powerpc/syscall.h
@@ -26,6 +26,7 @@
 #include <asm-generic/xenomai/syscall.h>
 
 #define __xn_mux_code(id,op)        ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
 
 #ifdef __KERNEL__
 
@@ -132,7 +133,7 @@ static inline int __xn_interrupted_p(str
 	register unsigned long __sc_6  __asm__ ("r6");		\
 	register unsigned long __sc_7  __asm__ ("r7");		\
 								\
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		\
+	LOADARGS_##nr(__xn_mux_code_shft(id,op), args);		\
 	__asm__ __volatile__					\
 		("sc           \n\t"				\
 		 "mfcr %0      "				\
Index: xenomai/ksrc/nucleus/shadow.c
===================================================================
--- xenomai.orig/ksrc/nucleus/shadow.c
+++ xenomai/ksrc/nucleus/shadow.c
@@ -1187,7 +1187,8 @@ static int xnshadow_sys_bind(struct task
 		return err;
 	}
 
-	return muxid;
+	/* return pre-shifted muxid - saves some cycles in user-space */
+	return __xn_mux_code(muxid,0);
 }
 
 static int xnshadow_sys_info(struct task_struct *curr, struct pt_regs *regs)


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Philippe Gerum]

On Thu, 2006-07-13 at 13:13 +0200, Jan Kiszka wrote:
> Hi,
> 
> some may recall the "micro-optimisation" thread I once started. Here is
> now a simple approach to deal with the yet suboptimal mux-code
> calculation in user-space. Code saving:
> 
> Before:
>    text    data     bss     dec     hex filename
>   18004     476       8   18488    4838 native/.libs/libnative.so
>   27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so
> 
> After:
>    text    data     bss     dec     hex filename
>   17172     476       8   17656    44f8 native/.libs/libnative.so
>   26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so
> 
> Of course, this also results in a few ops less being executed on each
> Xenomai syscall invocation (not many cycles, though).
> 
> Tested without problems on x86 so far.
> 

This is post 2.2 stuff since we need to check this critical change
against each and every supported arch. Since this breaks the ABI
including the ascending compatibility between old apps and new kernel
support, this won't make it during the v2 series either.

> Jan
> plain text document attachment (optimise-muxcode-calculation.patch)
> ---
>  include/asm-arm/syscall.h      |   25 +++++++++++++------------
>  include/asm-blackfin/syscall.h |    4 +++-
>  include/asm-i386/syscall.h     |    3 ++-
>  include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
>  include/asm-powerpc/syscall.h  |    3 ++-
>  ksrc/nucleus/shadow.c          |    3 ++-
>  6 files changed, 34 insertions(+), 27 deletions(-)
> 
> Index: xenomai/include/asm-arm/syscall.h
> ===================================================================
> --- xenomai.orig/include/asm-arm/syscall.h
> +++ xenomai/include/asm-arm/syscall.h
> @@ -26,6 +26,7 @@
>  #include <asm-generic/xenomai/syscall.h>
>  
>  #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))

+#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id)

should be enough.

<snip>

> Index: xenomai/include/asm-blackfin/syscall.h
> ===================================================================
> --- xenomai.orig/include/asm-blackfin/syscall.h
> +++ xenomai/include/asm-blackfin/syscall.h
> @@ -27,6 +27,7 @@
>     (i.e. negative syscall number in orig_p0 meaning "non-syscall
>     entry"). */
>  #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> +#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
>  

Breakage alert.

-- 
Philippe.

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1: Type: text/plain, Size: 3273 bytes --]

Philippe Gerum wrote:
> On Thu, 2006-07-13 at 13:13 +0200, Jan Kiszka wrote:
>> Hi,
>>
>> some may recall the "micro-optimisation" thread I once started. Here is
>> now a simple approach to deal with the yet suboptimal mux-code
>> calculation in user-space. Code saving:
>>
>> Before:
>>    text    data     bss     dec     hex filename
>>   18004     476       8   18488    4838 native/.libs/libnative.so
>>   27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so
>>
>> After:
>>    text    data     bss     dec     hex filename
>>   17172     476       8   17656    44f8 native/.libs/libnative.so
>>   26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so
>>
>> Of course, this also results in a few ops less being executed on each
>> Xenomai syscall invocation (not many cycles, though).
>>
>> Tested without problems on x86 so far.
>>
> 
> This is post 2.2 stuff since we need to check this critical change
> against each and every supported arch. 

Agree, there is no need to hurry in 2.2.

> Since this breaks the ABI
> including the ascending compatibility between old apps and new kernel
> support, this won't make it during the v2 series either.

The ABI chance just took place due to my laziness - I didn't want to
touch every skin library. Anyway, this ABI breakage can be avoided with
slightly more effort, i.e. by doing the shift in user-space during the
binding.

> 
>> Jan
>> plain text document attachment (optimise-muxcode-calculation.patch)
>> ---
>>  include/asm-arm/syscall.h      |   25 +++++++++++++------------
>>  include/asm-blackfin/syscall.h |    4 +++-
>>  include/asm-i386/syscall.h     |    3 ++-
>>  include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
>>  include/asm-powerpc/syscall.h  |    3 ++-
>>  ksrc/nucleus/shadow.c          |    3 ++-
>>  6 files changed, 34 insertions(+), 27 deletions(-)
>>
>> Index: xenomai/include/asm-arm/syscall.h
>> ===================================================================
>> --- xenomai.orig/include/asm-arm/syscall.h
>> +++ xenomai/include/asm-arm/syscall.h
>> @@ -26,6 +26,7 @@
>>  #include <asm-generic/xenomai/syscall.h>
>>  
>>  #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
>> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> 
> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id)
> 
> should be enough.

Given my current calculation of the muxid in the kernel, yes. But the
original variant has zero effect on the code and looks more consistent
to me.

> 
> <snip>
> 
>> Index: xenomai/include/asm-blackfin/syscall.h
>> ===================================================================
>> --- xenomai.orig/include/asm-blackfin/syscall.h
>> +++ xenomai/include/asm-blackfin/syscall.h
>> @@ -27,6 +27,7 @@
>>     (i.e. negative syscall number in orig_p0 meaning "non-syscall
>>     entry"). */
>>  #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
>> +#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
>>  
> 
> Breakage alert.
> 

Oops.

Ok, I will rework this patch.

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Philippe Gerum]

On Sat, 2006-07-15 at 10:06 +0200, Jan Kiszka wrote:
> Philippe Gerum wrote:
> > On Thu, 2006-07-13 at 13:13 +0200, Jan Kiszka wrote:
> >> Hi,
> >>
> >> some may recall the "micro-optimisation" thread I once started. Here is
> >> now a simple approach to deal with the yet suboptimal mux-code
> >> calculation in user-space. Code saving:
> >>
> >> Before:
> >>    text    data     bss     dec     hex filename
> >>   18004     476       8   18488    4838 native/.libs/libnative.so
> >>   27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so
> >>
> >> After:
> >>    text    data     bss     dec     hex filename
> >>   17172     476       8   17656    44f8 native/.libs/libnative.so
> >>   26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so
> >>
> >> Of course, this also results in a few ops less being executed on each
> >> Xenomai syscall invocation (not many cycles, though).
> >>
> >> Tested without problems on x86 so far.
> >>
> > 
> > This is post 2.2 stuff since we need to check this critical change
> > against each and every supported arch. 
> 
> Agree, there is no need to hurry in 2.2.
> 
> > Since this breaks the ABI
> > including the ascending compatibility between old apps and new kernel
> > support, this won't make it during the v2 series either.
> 
> The ABI chance just took place due to my laziness - I didn't want to
> touch every skin library. Anyway, this ABI breakage can be avoided with
> slightly more effort, i.e. by doing the shift in user-space during the
> binding.
> 

Yes, the mangling should be done in xeno_user_skin_init().

> > 
> >> Jan
> >> plain text document attachment (optimise-muxcode-calculation.patch)
> >> ---
> >>  include/asm-arm/syscall.h      |   25 +++++++++++++------------
> >>  include/asm-blackfin/syscall.h |    4 +++-
> >>  include/asm-i386/syscall.h     |    3 ++-
> >>  include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
> >>  include/asm-powerpc/syscall.h  |    3 ++-
> >>  ksrc/nucleus/shadow.c          |    3 ++-
> >>  6 files changed, 34 insertions(+), 27 deletions(-)
> >>
> >> Index: xenomai/include/asm-arm/syscall.h
> >> ===================================================================
> >> --- xenomai.orig/include/asm-arm/syscall.h
> >> +++ xenomai/include/asm-arm/syscall.h
> >> @@ -26,6 +26,7 @@
> >>  #include <asm-generic/xenomai/syscall.h>
> >>  
> >>  #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> >> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> > 
> > +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id)
> > 
> > should be enough.
> 
> Given my current calculation of the muxid in the kernel, yes. But the
> original variant has zero effect on the code and looks more consistent
> to me.

I don't get why actually. If the point is about reducing the number of
micro operations per syscall, then leaving this redundancy is pointless.
The relative obfuscation this optimization brings to the code is already
there, regardless of when the mux tag is crammed into the syscall code:
in any case, we have an half-baked syscall code which is going to be
adjusted at invocation time.

> 
> > 
> > <snip>
> > 
> >> Index: xenomai/include/asm-blackfin/syscall.h
> >> ===================================================================
> >> --- xenomai.orig/include/asm-blackfin/syscall.h
> >> +++ xenomai/include/asm-blackfin/syscall.h
> >> @@ -27,6 +27,7 @@
> >>     (i.e. negative syscall number in orig_p0 meaning "non-syscall
> >>     entry"). */
> >>  #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> >> +#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> >>  
> > 
> > Breakage alert.
> > 
> 
> Oops.
> 
> Ok, I will rework this patch.
> 
> Jan
> 
-- 
Philippe.

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1: Type: text/plain, Size: 4303 bytes --]

Philippe Gerum wrote:
> On Sat, 2006-07-15 at 10:06 +0200, Jan Kiszka wrote:
>> Philippe Gerum wrote:
>>> On Thu, 2006-07-13 at 13:13 +0200, Jan Kiszka wrote:
>>>> Hi,
>>>>
>>>> some may recall the "micro-optimisation" thread I once started. Here is
>>>> now a simple approach to deal with the yet suboptimal mux-code
>>>> calculation in user-space. Code saving:
>>>>
>>>> Before:
>>>>    text    data     bss     dec     hex filename
>>>>   18004     476       8   18488    4838 native/.libs/libnative.so
>>>>   27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so
>>>>
>>>> After:
>>>>    text    data     bss     dec     hex filename
>>>>   17172     476       8   17656    44f8 native/.libs/libnative.so
>>>>   26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so
>>>>
>>>> Of course, this also results in a few ops less being executed on each
>>>> Xenomai syscall invocation (not many cycles, though).
>>>>
>>>> Tested without problems on x86 so far.
>>>>
>>> This is post 2.2 stuff since we need to check this critical change
>>> against each and every supported arch. 
>> Agree, there is no need to hurry in 2.2.
>>
>>> Since this breaks the ABI
>>> including the ascending compatibility between old apps and new kernel
>>> support, this won't make it during the v2 series either.
>> The ABI chance just took place due to my laziness - I didn't want to
>> touch every skin library. Anyway, this ABI breakage can be avoided with
>> slightly more effort, i.e. by doing the shift in user-space during the
>> binding.
>>
> 
> Yes, the mangling should be done in xeno_user_skin_init().

Oh, great, I forgot the new common init code for the skin. This will help.

> 
>>>> Jan
>>>> plain text document attachment (optimise-muxcode-calculation.patch)
>>>> ---
>>>>  include/asm-arm/syscall.h      |   25 +++++++++++++------------
>>>>  include/asm-blackfin/syscall.h |    4 +++-
>>>>  include/asm-i386/syscall.h     |    3 ++-
>>>>  include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
>>>>  include/asm-powerpc/syscall.h  |    3 ++-
>>>>  ksrc/nucleus/shadow.c          |    3 ++-
>>>>  6 files changed, 34 insertions(+), 27 deletions(-)
>>>>
>>>> Index: xenomai/include/asm-arm/syscall.h
>>>> ===================================================================
>>>> --- xenomai.orig/include/asm-arm/syscall.h
>>>> +++ xenomai/include/asm-arm/syscall.h
>>>> @@ -26,6 +26,7 @@
>>>>  #include <asm-generic/xenomai/syscall.h>
>>>>  
>>>>  #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
>>>> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
>>> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id)
>>>
>>> should be enough.
>> Given my current calculation of the muxid in the kernel, yes. But the
>> original variant has zero effect on the code and looks more consistent
>> to me.
> 
> I don't get why actually. If the point is about reducing the number of
> micro operations per syscall, then leaving this redundancy is pointless.

As "op" is typically, well, always constant, that __xn_sys_mux bits are
just merge during compile time into the same constant.

> The relative obfuscation this optimization brings to the code is already
> there, regardless of when the mux tag is crammed into the syscall code:
> in any case, we have an half-baked syscall code which is going to be
> adjusted at invocation time.

My second approach will likely only shift the muxid ahead-of-time, thus
reduce obfuscation a bit again.

> 
>>> <snip>
>>>
>>>> Index: xenomai/include/asm-blackfin/syscall.h
>>>> ===================================================================
>>>> --- xenomai.orig/include/asm-blackfin/syscall.h
>>>> +++ xenomai/include/asm-blackfin/syscall.h
>>>> @@ -27,6 +27,7 @@
>>>>     (i.e. negative syscall number in orig_p0 meaning "non-syscall
>>>>     entry"). */
>>>>  #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
>>>> +#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
>>>>  
>>> Breakage alert.
>>>
>> Oops.
>>
>> Ok, I will rework this patch.
>>
>> Jan
>>



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Philippe Gerum]

On Sat, 2006-07-15 at 10:37 +0200, Jan Kiszka wrote:
> Philippe Gerum wrote:
> > On Sat, 2006-07-15 at 10:06 +0200, Jan Kiszka wrote:
> >> Philippe Gerum wrote:
> >>> On Thu, 2006-07-13 at 13:13 +0200, Jan Kiszka wrote:
> >>>> Hi,
> >>>>
> >>>> some may recall the "micro-optimisation" thread I once started. Here is
> >>>> now a simple approach to deal with the yet suboptimal mux-code
> >>>> calculation in user-space. Code saving:
> >>>>
> >>>> Before:
> >>>>    text    data     bss     dec     hex filename
> >>>>   18004     476       8   18488    4838 native/.libs/libnative.so
> >>>>   27445     696       4   28145    6df1 posix/.libs/libpthread_rt.so
> >>>>
> >>>> After:
> >>>>    text    data     bss     dec     hex filename
> >>>>   17172     476       8   17656    44f8 native/.libs/libnative.so
> >>>>   26805     696       4   27505    6b71 posix/.libs/libpthread_rt.so
> >>>>
> >>>> Of course, this also results in a few ops less being executed on each
> >>>> Xenomai syscall invocation (not many cycles, though).
> >>>>
> >>>> Tested without problems on x86 so far.
> >>>>
> >>> This is post 2.2 stuff since we need to check this critical change
> >>> against each and every supported arch. 
> >> Agree, there is no need to hurry in 2.2.
> >>
> >>> Since this breaks the ABI
> >>> including the ascending compatibility between old apps and new kernel
> >>> support, this won't make it during the v2 series either.
> >> The ABI chance just took place due to my laziness - I didn't want to
> >> touch every skin library. Anyway, this ABI breakage can be avoided with
> >> slightly more effort, i.e. by doing the shift in user-space during the
> >> binding.
> >>
> > 
> > Yes, the mangling should be done in xeno_user_skin_init().
> 
> Oh, great, I forgot the new common init code for the skin. This will help.
> 
> > 
> >>>> Jan
> >>>> plain text document attachment (optimise-muxcode-calculation.patch)
> >>>> ---
> >>>>  include/asm-arm/syscall.h      |   25 +++++++++++++------------
> >>>>  include/asm-blackfin/syscall.h |    4 +++-
> >>>>  include/asm-i386/syscall.h     |    3 ++-
> >>>>  include/asm-ia64/syscall.h     |   23 ++++++++++++-----------
> >>>>  include/asm-powerpc/syscall.h  |    3 ++-
> >>>>  ksrc/nucleus/shadow.c          |    3 ++-
> >>>>  6 files changed, 34 insertions(+), 27 deletions(-)
> >>>>
> >>>> Index: xenomai/include/asm-arm/syscall.h
> >>>> ===================================================================
> >>>> --- xenomai.orig/include/asm-arm/syscall.h
> >>>> +++ xenomai/include/asm-arm/syscall.h
> >>>> @@ -26,6 +26,7 @@
> >>>>  #include <asm-generic/xenomai/syscall.h>
> >>>>  
> >>>>  #define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> >>>> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> >>> +#define __xn_mux_code_shft(shifted_id,op) ((op << 24)|shifted_id)
> >>>
> >>> should be enough.
> >> Given my current calculation of the muxid in the kernel, yes. But the
> >> original variant has zero effect on the code and looks more consistent
> >> to me.
> > 
> > I don't get why actually. If the point is about reducing the number of
> > micro operations per syscall, then leaving this redundancy is pointless.
> 
> As "op" is typically, well, always constant, that __xn_sys_mux bits are
> just merge during compile time into the same constant.
> 

Exactly, this is part of what I called "relative obfuscation". If both
codes do the same thing, then one of them is one too many.

> > The relative obfuscation this optimization brings to the code is already
> > there, regardless of when the mux tag is crammed into the syscall code:
> > in any case, we have an half-baked syscall code which is going to be
> > adjusted at invocation time.
> 
> My second approach will likely only shift the muxid ahead-of-time, thus
> reduce obfuscation a bit again.
> 
> > 
> >>> <snip>
> >>>
> >>>> Index: xenomai/include/asm-blackfin/syscall.h
> >>>> ===================================================================
> >>>> --- xenomai.orig/include/asm-blackfin/syscall.h
> >>>> +++ xenomai/include/asm-blackfin/syscall.h
> >>>> @@ -27,6 +27,7 @@
> >>>>     (i.e. negative syscall number in orig_p0 meaning "non-syscall
> >>>>     entry"). */
> >>>>  #define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
> >>>> +#define __xn_mux_code_fast(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> >>>>  
> >>> Breakage alert.
> >>>
> >> Oops.
> >>
> >> Ok, I will rework this patch.
> >>
> >> Jan
> >>
> 
> 
-- 
Philippe.

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1.1: Type: text/plain, Size: 810 bytes --]

Jan Kiszka wrote:
> ...
> Ok, I will rework this patch.
> 

And here is -v2 (for post 2.2 trunk). It keeps the ABI but changes the
API wrt __xeno_mux_code. As this change gets widely caught by
xeno_user_skin_init, the modifications are limited.

At this chance I also converted the rtdm library to the generic
initialisation code. I tweaked nucleus/bind.h a bit so that one can
control via XENO_DISABLE_MLOCKALL_DETECTION if the related code gets
built into the lib. This appeared to be reasonable to me because librtdm
doesn't create its own RT threads, thus the check should be better left
to those skins who do so. Anyone any better idea, or is this acceptable?
If a separate patch is preferred, I will break out this change.

Tested of x86, other archs need review and/or testing.

Jan

[-- Attachment #1.2: optimise-muxcode-calculation-v2.patch --]
[-- Type: text/plain, Size: 11048 bytes --]

---
 include/asm-arm/syscall.h      |   29 ++++++++++++------------
 include/asm-blackfin/syscall.h |    6 +++--
 include/asm-i386/syscall.h     |    7 +++--
 include/asm-ia64/syscall.h     |   25 ++++++++++----------
 include/asm-powerpc/syscall.h  |    7 +++--
 include/nucleus/bind.h         |   19 ++++++++++-----
 src/skins/rtdm/init.c          |   49 +++--------------------------------------
 7 files changed, 56 insertions(+), 86 deletions(-)

Index: xenomai/include/asm-arm/syscall.h
===================================================================
--- xenomai.orig/include/asm-arm/syscall.h
+++ xenomai/include/asm-arm/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #define XENO_ARM_SYSCALL        0x009F0042	/* carefully chosen... */
 
@@ -130,20 +131,20 @@ static inline int __xn_interrupted_p(str
 #define __sys2(x)	#x
 #define __sys1(x)	__sys2(x)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
-  ({								                    \
-        unsigned long __res;					        \
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
+  ({								\
+        unsigned long __res;					\
 	register unsigned long __res_r0 __asm__ ("r0");		\
-   	ASM_INDECL_##nr;					                \
-								                        \
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		    \
-	__asm__ __volatile__ (					            \
-"       swi " __sys1(XENO_ARM_SYSCALL)			        \
-		: "=r" (__res_r0)				                \
-		: ASM_INPUT_##nr				                \
-		: "memory");					                \
-   	__res = __res_r0;					                \
-   	(int) __res;						                \
+   	ASM_INDECL_##nr;					\
+								\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
+	__asm__ __volatile__ (					\
+"       swi " __sys1(XENO_ARM_SYSCALL)				\
+		: "=r" (__res_r0)				\
+		: ASM_INPUT_##nr				\
+		: "memory");					\
+   	__res = __res_r0;					\
+   	(int) __res;						\
   })
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
Index: xenomai/include/asm-blackfin/syscall.h
===================================================================
--- xenomai.orig/include/asm-blackfin/syscall.h
+++ xenomai/include/asm-blackfin/syscall.h
@@ -26,7 +26,8 @@
    marker. Note: watch out for the p0 sign convention used by Linux
    (i.e. negative syscall number in orig_p0 meaning "non-syscall
    entry"). */
-#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) (id << 24)
 
 /* Local syscalls -- the braindamage thing about this arch is the
    absence of atomic ops usable from user-space; so we export what
@@ -213,7 +214,8 @@ static inline int __xn_interrupted_p(str
   __res;								\
 })
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)	__emit_syscall##nr(__xn_mux_code(id,op), ##args)
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...) \
+    __emit_syscall##nr(__xn_mux_code(shifted_id,op), ##args)
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
 #define XENOMAI_SYSCALL1(op,a1)             XENOMAI_DO_SYSCALL(1,0,op,a1)
Index: xenomai/include/asm-i386/syscall.h
===================================================================
--- xenomai.orig/include/asm-i386/syscall.h
+++ xenomai/include/asm-i386/syscall.h
@@ -22,7 +22,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)  ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -165,9 +166,9 @@ asm (".L__X'%ebx = 1\n\t"
     : "i" (__xn_mux_code(0,op)) ASMFMT_##nr(args) : "memory", "cc");  \
     (int) resultvar; })
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...) \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...) \
   ({								      \
-    int muxcode = __xn_mux_code(id,op);                               \
+    int muxcode = __xn_mux_code(shifted_id,op);			      \
     unsigned resultvar;						      \
     asm volatile (						      \
     LOADARGS_##nr						      \
Index: xenomai/include/asm-ia64/syscall.h
===================================================================
--- xenomai.orig/include/asm-ia64/syscall.h
+++ xenomai/include/asm-ia64/syscall.h
@@ -23,7 +23,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|(((id << 16) & 0xff0000UL)|(__xn_sys_mux & 0xffffUL)))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffffUL))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000UL)
 
 #ifdef __KERNEL__
 
@@ -151,17 +152,17 @@ static inline int __xn_interrupted_p(str
   /* Branch registers.  */						\
   "b6", "b7"
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...)                   \
-  ({                                                            \
-    register long _r15 asm ("r15") = (__xn_mux_code(id,op));    \
-    register long _retval asm ("r8");                           \
-    register long err asm ("r10");                              \
-    LOAD_ARGS_##nr (args);                                      \
-    __asm __volatile ("break %3;;\n\t"                          \
-                      : "=r" (_retval), "=r" (_r15), "=r" (err) \
-                      : "i" (__BREAK_SYSCALL), "1" (_r15)       \
-			ASM_ARGS_##nr                           \
-                      : "memory" ASM_CLOBBERS_##nr);            \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...)			\
+  ({									\
+    register long _r15 asm ("r15") = (__xn_mux_code(shifted_id,op));	\
+    register long _retval asm ("r8");					\
+    register long err asm ("r10");					\
+    LOAD_ARGS_##nr (args);						\
+    __asm __volatile ("break %3;;\n\t"					\
+		      : "=r" (_retval), "=r" (_r15), "=r" (err)		\
+		      : "i" (__BREAK_SYSCALL), "1" (_r15)		\
+			ASM_ARGS_##nr					\
+		      : "memory" ASM_CLOBBERS_##nr);			\
     err < 0 ? -_retval : _retval; })
 
 #define XENOMAI_SYS_MUX(nr, op, args...) XENOMAI_SKIN_MUX(nr, 0, op , ##args)
Index: xenomai/include/asm-powerpc/syscall.h
===================================================================
--- xenomai.orig/include/asm-powerpc/syscall.h
+++ xenomai/include/asm-powerpc/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -123,7 +124,7 @@ static inline int __xn_interrupted_p(str
 #define ASM_INPUT_4 ASM_INPUT_3, "4" (__sc_6)
 #define ASM_INPUT_5 ASM_INPUT_4, "5" (__sc_7)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
   ({								\
 	register unsigned long __sc_0  __asm__ ("r0");		\
 	register unsigned long __sc_3  __asm__ ("r3");		\
@@ -132,7 +133,7 @@ static inline int __xn_interrupted_p(str
 	register unsigned long __sc_6  __asm__ ("r6");		\
 	register unsigned long __sc_7  __asm__ ("r7");		\
 								\
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
 	__asm__ __volatile__					\
 		("sc           \n\t"				\
 		 "mfcr %0      "				\
Index: xenomai/include/nucleus/bind.h
===================================================================
--- xenomai.orig/include/nucleus/bind.h
+++ xenomai/include/nucleus/bind.h
@@ -9,6 +9,7 @@
 #include <pthread.h>
 #include <asm/xenomai/syscall.h>
 
+#ifndef XENO_DISABLE_MLOCKALL_DETECTION
 __attribute__((weak)) int xeno_sigxcpu_no_mlock = 1;
 
 static void  xeno_handle_mlock_alert (int sig)
@@ -34,11 +35,11 @@ static void  xeno_handle_mlock_alert (in
 	pthread_kill(pthread_self(),SIGXCPU);
 	}
 }
+#endif /* !XENO_DISABLE_MLOCKALL_DETECTION */
 
 static inline int
 xeno_user_skin_init(unsigned skin_magic, const char *skin, const char *module)
 {
-    struct sigaction sa;
     xnfeatinfo_t finfo;
     int muxid;
 
@@ -80,15 +81,19 @@ xeno_user_skin_init(unsigned skin_magic,
         exit(1);
         }
 
+#ifndef XENO_DISABLE_MLOCKALL_DETECTION
     /* Install a SIGXCPU handler to intercept alerts about unlocked
        process memory. */
+    {
+        struct sigaction sa;
+        sa.sa_handler = &xeno_handle_mlock_alert;
+        sigemptyset(&sa.sa_mask);
+        sa.sa_flags = 0;
+        sigaction(SIGXCPU,&sa,NULL);
+    }
+#endif /* !XENO_DISABLE_MLOCKALL_DETECTION */
 
-    sa.sa_handler = &xeno_handle_mlock_alert;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = 0;
-    sigaction(SIGXCPU,&sa,NULL);
-
-    return muxid;
+    return __xn_mux_shifted_id(muxid);
 }
 
 #endif /* _XENO_NUCLEUS_BIND_H */
Index: xenomai/src/skins/rtdm/init.c
===================================================================
--- xenomai.orig/src/skins/rtdm/init.c
+++ xenomai/src/skins/rtdm/init.c
@@ -20,6 +20,9 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+
+#define XENO_DISABLE_MLOCKALL_DETECTION
+#include <nucleus/bind.h>
 #include <rtdm/syscall.h>
 
 int __rtdm_muxid = -1;
@@ -27,49 +30,5 @@ int __rtdm_muxid = -1;
 static __attribute__((constructor)) void __init_rtdm_interface(void)
 
 {
-    xnfeatinfo_t finfo;
-    int muxid;
-
-#ifdef xeno_arch_features_check
-    xeno_arch_features_check();
-#endif /* xeno_arch_features_check */
-
-    muxid = XENOMAI_SYSBIND(RTDM_SKIN_MAGIC,
-			    XENOMAI_FEAT_DEP,
-			    XENOMAI_ABI_REV,
-			    &finfo);
-    switch (muxid)
-	{
-	case -EINVAL:
-
-	    fprintf(stderr,"Xenomai: incompatible feature set\n");
-	    fprintf(stderr,"(required=\"%s\", present=\"%s\", missing=\"%s\").\n",
-		    finfo.feat_man_s,finfo.feat_all_s,finfo.feat_mis_s);
-	    exit(1);
-
-	case -ENOEXEC:
-
-	    fprintf(stderr,"Xenomai: incompatible ABI revision level\n");
-	    fprintf(stderr,"(needed=%lu, current=%lu).\n",
-		    XENOMAI_ABI_REV,finfo.abirev);
-	    exit(1);
-
-	case -ENOSYS:
-	case -ESRCH:
-
-	    /* we ignore this and fail later when the user tries to open
-	       a device or socket. */
-	    break;
-
-	default:
-
-	    if (muxid < 0)
-		{
-		fprintf(stderr,"Xenomai: binding failed: %s.\n",strerror(-muxid));
-		exit(1);
-		}
-
-	    __rtdm_muxid = muxid;
-	    break;
-	}
+    __rtdm_muxid = xeno_user_skin_init(RTDM_SKIN_MAGIC, "rtdm", "xeno_rtdm");
 }


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Gilles Chanteperdrix]

Jan Kiszka wrote:
 > Index: xenomai/include/asm-blackfin/syscall.h
 > ===================================================================
 > --- xenomai.orig/include/asm-blackfin/syscall.h
 > +++ xenomai/include/asm-blackfin/syscall.h
 > @@ -26,7 +26,8 @@
 >     marker. Note: watch out for the p0 sign convention used by Linux
 >     (i.e. negative syscall number in orig_p0 meaning "non-syscall
 >     entry"). */
 > -#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
 > +#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))

Should not this be (op << 16) ?

 > +#define __xn_mux_shifted_id(id) (id << 24)


-- 


					    Gilles Chanteperdrix.

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1.1: Type: text/plain, Size: 758 bytes --]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>  > Index: xenomai/include/asm-blackfin/syscall.h
>  > ===================================================================
>  > --- xenomai.orig/include/asm-blackfin/syscall.h
>  > +++ xenomai/include/asm-blackfin/syscall.h
>  > @@ -26,7 +26,8 @@
>  >     marker. Note: watch out for the p0 sign convention used by Linux
>  >     (i.e. negative syscall number in orig_p0 meaning "non-syscall
>  >     entry"). */
>  > -#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
>  > +#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
> 
> Should not this be (op << 16) ?
> 

Yes, corrected version attached.

Thanks,
Jan

[-- Attachment #1.2: optimise-muxcode-calculation-v3.patch --]
[-- Type: text/plain, Size: 11059 bytes --]

---
 include/asm-arm/syscall.h      |   29 ++++++++++++------------
 include/asm-blackfin/syscall.h |    6 +++--
 include/asm-i386/syscall.h     |    7 +++--
 include/asm-ia64/syscall.h     |   25 ++++++++++----------
 include/asm-powerpc/syscall.h  |    7 +++--
 include/nucleus/bind.h         |   19 ++++++++++-----
 src/skins/rtdm/init.c          |   49 +++--------------------------------------
 7 files changed, 56 insertions(+), 86 deletions(-)

Index: xenomai/include/asm-arm/syscall.h
===================================================================
--- xenomai.orig/include/asm-arm/syscall.h
+++ xenomai/include/asm-arm/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #define XENO_ARM_SYSCALL        0x009F0042	/* carefully chosen... */
 
@@ -130,20 +131,20 @@ static inline int __xn_interrupted_p(str
 #define __sys2(x)	#x
 #define __sys1(x)	__sys2(x)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
-  ({								                    \
-        unsigned long __res;					        \
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
+  ({								\
+        unsigned long __res;					\
 	register unsigned long __res_r0 __asm__ ("r0");		\
-   	ASM_INDECL_##nr;					                \
-								                        \
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		    \
-	__asm__ __volatile__ (					            \
-"       swi " __sys1(XENO_ARM_SYSCALL)			        \
-		: "=r" (__res_r0)				                \
-		: ASM_INPUT_##nr				                \
-		: "memory");					                \
-   	__res = __res_r0;					                \
-   	(int) __res;						                \
+   	ASM_INDECL_##nr;					\
+								\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
+	__asm__ __volatile__ (					\
+"       swi " __sys1(XENO_ARM_SYSCALL)				\
+		: "=r" (__res_r0)				\
+		: ASM_INPUT_##nr				\
+		: "memory");					\
+   	__res = __res_r0;					\
+   	(int) __res;						\
   })
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
Index: xenomai/include/asm-blackfin/syscall.h
===================================================================
--- xenomai.orig/include/asm-blackfin/syscall.h
+++ xenomai/include/asm-blackfin/syscall.h
@@ -26,7 +26,8 @@
    marker. Note: watch out for the p0 sign convention used by Linux
    (i.e. negative syscall number in orig_p0 meaning "non-syscall
    entry"). */
-#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) (shifted_id|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) (id << 24)
 
 /* Local syscalls -- the braindamage thing about this arch is the
    absence of atomic ops usable from user-space; so we export what
@@ -213,7 +214,8 @@ static inline int __xn_interrupted_p(str
   __res;								\
 })
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)	__emit_syscall##nr(__xn_mux_code(id,op), ##args)
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...) \
+    __emit_syscall##nr(__xn_mux_code(shifted_id,op), ##args)
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
 #define XENOMAI_SYSCALL1(op,a1)             XENOMAI_DO_SYSCALL(1,0,op,a1)
Index: xenomai/include/asm-i386/syscall.h
===================================================================
--- xenomai.orig/include/asm-i386/syscall.h
+++ xenomai/include/asm-i386/syscall.h
@@ -22,7 +22,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)  ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -165,9 +166,9 @@ asm (".L__X'%ebx = 1\n\t"
     : "i" (__xn_mux_code(0,op)) ASMFMT_##nr(args) : "memory", "cc");  \
     (int) resultvar; })
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...) \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...) \
   ({								      \
-    int muxcode = __xn_mux_code(id,op);                               \
+    int muxcode = __xn_mux_code(shifted_id,op);			      \
     unsigned resultvar;						      \
     asm volatile (						      \
     LOADARGS_##nr						      \
Index: xenomai/include/asm-ia64/syscall.h
===================================================================
--- xenomai.orig/include/asm-ia64/syscall.h
+++ xenomai/include/asm-ia64/syscall.h
@@ -23,7 +23,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|(((id << 16) & 0xff0000UL)|(__xn_sys_mux & 0xffffUL)))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffffUL))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000UL)
 
 #ifdef __KERNEL__
 
@@ -151,17 +152,17 @@ static inline int __xn_interrupted_p(str
   /* Branch registers.  */						\
   "b6", "b7"
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...)                   \
-  ({                                                            \
-    register long _r15 asm ("r15") = (__xn_mux_code(id,op));    \
-    register long _retval asm ("r8");                           \
-    register long err asm ("r10");                              \
-    LOAD_ARGS_##nr (args);                                      \
-    __asm __volatile ("break %3;;\n\t"                          \
-                      : "=r" (_retval), "=r" (_r15), "=r" (err) \
-                      : "i" (__BREAK_SYSCALL), "1" (_r15)       \
-			ASM_ARGS_##nr                           \
-                      : "memory" ASM_CLOBBERS_##nr);            \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...)			\
+  ({									\
+    register long _r15 asm ("r15") = (__xn_mux_code(shifted_id,op));	\
+    register long _retval asm ("r8");					\
+    register long err asm ("r10");					\
+    LOAD_ARGS_##nr (args);						\
+    __asm __volatile ("break %3;;\n\t"					\
+		      : "=r" (_retval), "=r" (_r15), "=r" (err)		\
+		      : "i" (__BREAK_SYSCALL), "1" (_r15)		\
+			ASM_ARGS_##nr					\
+		      : "memory" ASM_CLOBBERS_##nr);			\
     err < 0 ? -_retval : _retval; })
 
 #define XENOMAI_SYS_MUX(nr, op, args...) XENOMAI_SKIN_MUX(nr, 0, op , ##args)
Index: xenomai/include/asm-powerpc/syscall.h
===================================================================
--- xenomai.orig/include/asm-powerpc/syscall.h
+++ xenomai/include/asm-powerpc/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -123,7 +124,7 @@ static inline int __xn_interrupted_p(str
 #define ASM_INPUT_4 ASM_INPUT_3, "4" (__sc_6)
 #define ASM_INPUT_5 ASM_INPUT_4, "5" (__sc_7)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
   ({								\
 	register unsigned long __sc_0  __asm__ ("r0");		\
 	register unsigned long __sc_3  __asm__ ("r3");		\
@@ -132,7 +133,7 @@ static inline int __xn_interrupted_p(str
 	register unsigned long __sc_6  __asm__ ("r6");		\
 	register unsigned long __sc_7  __asm__ ("r7");		\
 								\
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
 	__asm__ __volatile__					\
 		("sc           \n\t"				\
 		 "mfcr %0      "				\
Index: xenomai/include/nucleus/bind.h
===================================================================
--- xenomai.orig/include/nucleus/bind.h
+++ xenomai/include/nucleus/bind.h
@@ -9,6 +9,7 @@
 #include <pthread.h>
 #include <asm/xenomai/syscall.h>
 
+#ifndef XENO_DISABLE_MLOCKALL_DETECTION
 __attribute__((weak)) int xeno_sigxcpu_no_mlock = 1;
 
 static void  xeno_handle_mlock_alert (int sig)
@@ -34,11 +35,11 @@ static void  xeno_handle_mlock_alert (in
 	pthread_kill(pthread_self(),SIGXCPU);
 	}
 }
+#endif /* !XENO_DISABLE_MLOCKALL_DETECTION */
 
 static inline int
 xeno_user_skin_init(unsigned skin_magic, const char *skin, const char *module)
 {
-    struct sigaction sa;
     xnfeatinfo_t finfo;
     int muxid;
 
@@ -80,15 +81,19 @@ xeno_user_skin_init(unsigned skin_magic,
         exit(1);
         }
 
+#ifndef XENO_DISABLE_MLOCKALL_DETECTION
     /* Install a SIGXCPU handler to intercept alerts about unlocked
        process memory. */
+    {
+        struct sigaction sa;
+        sa.sa_handler = &xeno_handle_mlock_alert;
+        sigemptyset(&sa.sa_mask);
+        sa.sa_flags = 0;
+        sigaction(SIGXCPU,&sa,NULL);
+    }
+#endif /* !XENO_DISABLE_MLOCKALL_DETECTION */
 
-    sa.sa_handler = &xeno_handle_mlock_alert;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = 0;
-    sigaction(SIGXCPU,&sa,NULL);
-
-    return muxid;
+    return __xn_mux_shifted_id(muxid);
 }
 
 #endif /* _XENO_NUCLEUS_BIND_H */
Index: xenomai/src/skins/rtdm/init.c
===================================================================
--- xenomai.orig/src/skins/rtdm/init.c
+++ xenomai/src/skins/rtdm/init.c
@@ -20,6 +20,9 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+
+#define XENO_DISABLE_MLOCKALL_DETECTION
+#include <nucleus/bind.h>
 #include <rtdm/syscall.h>
 
 int __rtdm_muxid = -1;
@@ -27,49 +30,5 @@ int __rtdm_muxid = -1;
 static __attribute__((constructor)) void __init_rtdm_interface(void)
 
 {
-    xnfeatinfo_t finfo;
-    int muxid;
-
-#ifdef xeno_arch_features_check
-    xeno_arch_features_check();
-#endif /* xeno_arch_features_check */
-
-    muxid = XENOMAI_SYSBIND(RTDM_SKIN_MAGIC,
-			    XENOMAI_FEAT_DEP,
-			    XENOMAI_ABI_REV,
-			    &finfo);
-    switch (muxid)
-	{
-	case -EINVAL:
-
-	    fprintf(stderr,"Xenomai: incompatible feature set\n");
-	    fprintf(stderr,"(required=\"%s\", present=\"%s\", missing=\"%s\").\n",
-		    finfo.feat_man_s,finfo.feat_all_s,finfo.feat_mis_s);
-	    exit(1);
-
-	case -ENOEXEC:
-
-	    fprintf(stderr,"Xenomai: incompatible ABI revision level\n");
-	    fprintf(stderr,"(needed=%lu, current=%lu).\n",
-		    XENOMAI_ABI_REV,finfo.abirev);
-	    exit(1);
-
-	case -ENOSYS:
-	case -ESRCH:
-
-	    /* we ignore this and fail later when the user tries to open
-	       a device or socket. */
-	    break;
-
-	default:
-
-	    if (muxid < 0)
-		{
-		fprintf(stderr,"Xenomai: binding failed: %s.\n",strerror(-muxid));
-		exit(1);
-		}
-
-	    __rtdm_muxid = muxid;
-	    break;
-	}
+    __rtdm_muxid = xeno_user_skin_init(RTDM_SKIN_MAGIC, "rtdm", "xeno_rtdm");
 }

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Gilles Chanteperdrix]

Jan Kiszka wrote:
 > Jan Kiszka wrote:
 > > ...
 > > Ok, I will rework this patch.
 > > 
 > 
 > And here is -v2 (for post 2.2 trunk). It keeps the ABI but changes the
 > API wrt __xeno_mux_code. As this change gets widely caught by
 > xeno_user_skin_init, the modifications are limited.
 > 
 > At this chance I also converted the rtdm library to the generic
 > initialisation code. I tweaked nucleus/bind.h a bit so that one can
 > control via XENO_DISABLE_MLOCKALL_DETECTION if the related code gets
 > built into the lib. This appeared to be reasonable to me because librtdm
 > doesn't create its own RT threads, thus the check should be better left
 > to those skins who do so. Anyone any better idea, or is this acceptable?
 > If a separate patch is preferred, I will break out this change.

Another reason why rtdm did not use the generic initialization code is
that RTDM did not call exit upon failure to bind, and let a later call
to open fail. I do not know if it was desirable, but it was a feature of
the previous implementation.

-- 


					    Gilles Chanteperdrix.

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1.1: Type: text/plain, Size: 1674 bytes --]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>  > Jan Kiszka wrote:
>  > > ...
>  > > Ok, I will rework this patch.
>  > > 
>  > 
>  > And here is -v2 (for post 2.2 trunk). It keeps the ABI but changes the
>  > API wrt __xeno_mux_code. As this change gets widely caught by
>  > xeno_user_skin_init, the modifications are limited.
>  > 
>  > At this chance I also converted the rtdm library to the generic
>  > initialisation code. I tweaked nucleus/bind.h a bit so that one can
>  > control via XENO_DISABLE_MLOCKALL_DETECTION if the related code gets
>  > built into the lib. This appeared to be reasonable to me because librtdm
>  > doesn't create its own RT threads, thus the check should be better left
>  > to those skins who do so. Anyone any better idea, or is this acceptable?
>  > If a separate patch is preferred, I will break out this change.
> 
> Another reason why rtdm did not use the generic initialization code is
> that RTDM did not call exit upon failure to bind, and let a later call
> to open fail. I do not know if it was desirable, but it was a feature of
> the previous implementation.
> 

Damn right. So let's try this more systematically:

The first patch prepares the generic skin-init code for the usage by
rtdm/init.c. I'm not totally happy with the #ifndef tweak. I would
prefer to control the signal setup also via a flag, but I have no idea
how to avoid linking the unused xeno_handle_mlock_alert into librtdm.
Any ideas?

Based on this conversion is the optimisation patch -v4. There was
another quirk hidden in libpthread_rt which binds to RTDM "manually".
That's now also covered by the patch.

Jan

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1.2: generic-skin-init.patch --]
[-- Type: text/x-patch; name="generic-skin-init.patch", Size: 7650 bytes --]

---
 include/nucleus/bind.h   |   43 +++++++++++++++++++++++-------------
 src/skins/native/init.c  |    2 -
 src/skins/posix/init.c   |    2 -
 src/skins/rtai/init.c    |    2 -
 src/skins/rtdm/init.c    |   55 ++++++++---------------------------------------
 src/skins/uvm/init.c     |    3 +-
 src/skins/vrtx/init.c    |    2 -
 src/skins/vxworks/init.c |    2 -
 8 files changed, 45 insertions(+), 66 deletions(-)

Index: xenomai/include/nucleus/bind.h
===================================================================
--- xenomai.orig/include/nucleus/bind.h
+++ xenomai/include/nucleus/bind.h
@@ -9,6 +9,9 @@
 #include <pthread.h>
 #include <asm/xenomai/syscall.h>
 
+#define XNSKIN_LAZY_BIND_FAIL	0x01 /* do not fail on missing skin */
+
+#ifndef XNSKIN_NO_MLOCK_ALERT
 __attribute__((weak)) int xeno_sigxcpu_no_mlock = 1;
 
 static void  xeno_handle_mlock_alert (int sig)
@@ -34,18 +37,19 @@ static void  xeno_handle_mlock_alert (in
 	pthread_kill(pthread_self(),SIGXCPU);
 	}
 }
+#endif /* !XNSKIN_NO_MLOCK_ALERT */
 
 static inline int
-xeno_user_skin_init(unsigned skin_magic, const char *skin, const char *module)
+xeno_user_skin_init(unsigned skin_magic, const char *skin, const char *module,
+		    int flags)
 {
-    struct sigaction sa;
     xnfeatinfo_t finfo;
-    int muxid;
+    int muxid = -1;
 
 #ifdef xeno_arch_features_check
     xeno_arch_features_check();
 #endif /* xeno_arch_features_check */
-    
+
     muxid = XENOMAI_SYSBIND(skin_magic,
 			    XENOMAI_FEAT_DEP,
 			    XENOMAI_ABI_REV,
@@ -69,24 +73,33 @@ xeno_user_skin_init(unsigned skin_magic,
 	case -ENOSYS:
 	case -ESRCH:
 
+	    if (flags & XNSKIN_LAZY_BIND_FAIL)
+		break; /* We are ordered to ignore the missing skin. */
+
 	    fprintf(stderr,"Xenomai: %s skin or CONFIG_XENO_OPT_PERVASIVE disabled.\n"
-                    "(modprobe %s?)\n", skin, module);
+		    "(modprobe %s?)\n", skin, module);
 	    exit(1);
-        }
-    
-    if (muxid < 0)
-        {
-        fprintf(stderr,"Xenomai: binding failed: %s.\n",strerror(-muxid));
-        exit(1);
+
+	default:
+	    if (muxid < 0)
+		{
+		fprintf(stderr,"Xenomai: binding failed: %s.\n",strerror(-muxid));
+		exit(1);
+		}
         }
 
+#ifndef XNSKIN_NO_MLOCK_ALERT
     /* Install a SIGXCPU handler to intercept alerts about unlocked
        process memory. */
+    {
+	struct sigaction sa;
 
-    sa.sa_handler = &xeno_handle_mlock_alert;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = 0;
-    sigaction(SIGXCPU,&sa,NULL);
+	sa.sa_handler = &xeno_handle_mlock_alert;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = 0;
+	sigaction(SIGXCPU,&sa,NULL);
+    }
+#endif /* !XNSKIN_NO_MLOCK_ALERT */
 
     return muxid;
 }
Index: xenomai/src/skins/native/init.c
===================================================================
--- xenomai.orig/src/skins/native/init.c
+++ xenomai/src/skins/native/init.c
@@ -39,7 +39,7 @@ static __attribute__ ((constructor))
 void __init_xeno_interface(void)
 {
 	__native_muxid =
-	    xeno_user_skin_init(XENO_SKIN_MAGIC, "native", "xeno_native");
+	    xeno_user_skin_init(XENO_SKIN_MAGIC, "native", "xeno_native", 0);
 
 	/* Allocate a TSD key for indexing self task pointers. */
 
Index: xenomai/src/skins/posix/init.c
===================================================================
--- xenomai.orig/src/skins/posix/init.c
+++ xenomai/src/skins/posix/init.c
@@ -40,7 +40,7 @@ void __init_posix_interface(void)
 	int muxid, err;
 
 	__pse51_muxid =
-	    xeno_user_skin_init(PSE51_SKIN_MAGIC, "POSIX", "xeno_posix");
+	    xeno_user_skin_init(PSE51_SKIN_MAGIC, "POSIX", "xeno_posix", 0);
 
 	muxid = XENOMAI_SYSBIND(RTDM_SKIN_MAGIC,
 				XENOMAI_FEAT_DEP, XENOMAI_ABI_REV, NULL);
Index: xenomai/src/skins/rtai/init.c
===================================================================
--- xenomai.orig/src/skins/rtai/init.c
+++ xenomai/src/skins/rtai/init.c
@@ -27,5 +27,5 @@ static __attribute__ ((constructor))
 void __init_rtai_interface(void)
 {
 	__rtai_muxid =
-	    xeno_user_skin_init(RTAI_SKIN_MAGIC, "RTAI", "xeno_rtai");
+	    xeno_user_skin_init(RTAI_SKIN_MAGIC, "RTAI", "xeno_rtai", 0);
 }
Index: xenomai/src/skins/rtdm/init.c
===================================================================
--- xenomai.orig/src/skins/rtdm/init.c
+++ xenomai/src/skins/rtdm/init.c
@@ -20,6 +20,11 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+
+/* Checking for mlockall is only done by skins that create real-time
+   user-space threads, which we do not. */
+#define XNSKIN_NO_MLOCK_ALERT
+#include <nucleus/bind.h>
 #include <rtdm/syscall.h>
 
 int __rtdm_muxid = -1;
@@ -27,49 +32,9 @@ int __rtdm_muxid = -1;
 static __attribute__((constructor)) void __init_rtdm_interface(void)
 
 {
-    xnfeatinfo_t finfo;
-    int muxid;
-
-#ifdef xeno_arch_features_check
-    xeno_arch_features_check();
-#endif /* xeno_arch_features_check */
-
-    muxid = XENOMAI_SYSBIND(RTDM_SKIN_MAGIC,
-			    XENOMAI_FEAT_DEP,
-			    XENOMAI_ABI_REV,
-			    &finfo);
-    switch (muxid)
-	{
-	case -EINVAL:
-
-	    fprintf(stderr,"Xenomai: incompatible feature set\n");
-	    fprintf(stderr,"(required=\"%s\", present=\"%s\", missing=\"%s\").\n",
-		    finfo.feat_man_s,finfo.feat_all_s,finfo.feat_mis_s);
-	    exit(1);
-
-	case -ENOEXEC:
-
-	    fprintf(stderr,"Xenomai: incompatible ABI revision level\n");
-	    fprintf(stderr,"(needed=%lu, current=%lu).\n",
-		    XENOMAI_ABI_REV,finfo.abirev);
-	    exit(1);
-
-	case -ENOSYS:
-	case -ESRCH:
-
-	    /* we ignore this and fail later when the user tries to open
-	       a device or socket. */
-	    break;
-
-	default:
-
-	    if (muxid < 0)
-		{
-		fprintf(stderr,"Xenomai: binding failed: %s.\n",strerror(-muxid));
-		exit(1);
-		}
-
-	    __rtdm_muxid = muxid;
-	    break;
-	}
+	/* We ignore a missing skin and fail later when the user tries to open
+	   a device or socket. */
+	__rtdm_muxid =
+	    xeno_user_skin_init(RTDM_SKIN_MAGIC, "RTDM", "xeno_rtdm",
+				XNSKIN_LAZY_BIND_FAIL);
 }
Index: xenomai/src/skins/uvm/init.c
===================================================================
--- xenomai.orig/src/skins/uvm/init.c
+++ xenomai/src/skins/uvm/init.c
@@ -29,7 +29,8 @@ xnsysinfo_t __uvm_info;
 static __attribute__ ((constructor))
 void __init_uvm_interface(void)
 {
-	__uvm_muxid = xeno_user_skin_init(UVM_SKIN_MAGIC, "UVM", "xeno_uvm");
+	__uvm_muxid =
+	    xeno_user_skin_init(UVM_SKIN_MAGIC, "UVM", "xeno_uvm", 0);
 
 	XENOMAI_SYSCALL2(__xn_sys_info, __uvm_muxid, &__uvm_info);
 }
Index: xenomai/src/skins/vrtx/init.c
===================================================================
--- xenomai.orig/src/skins/vrtx/init.c
+++ xenomai/src/skins/vrtx/init.c
@@ -40,7 +40,7 @@ void __init_xeno_interface(void)
 	TCB *tcb;
 
 	__vrtx_muxid =
-	    xeno_user_skin_init(VRTX_SKIN_MAGIC, "VRTX", "xeno_vrtx");
+	    xeno_user_skin_init(VRTX_SKIN_MAGIC, "VRTX", "xeno_vrtx", 0);
 
 	/* Allocate a TSD key for indexing self task pointers. */
 
Index: xenomai/src/skins/vxworks/init.c
===================================================================
--- xenomai.orig/src/skins/vxworks/init.c
+++ xenomai/src/skins/vxworks/init.c
@@ -38,7 +38,7 @@ static __attribute__ ((constructor))
 void __init_xeno_interface(void)
 {
 	__vxworks_muxid = xeno_user_skin_init(VXWORKS_SKIN_MAGIC,
-					      "VxWorks", "xeno_vxworks");
+					      "VxWorks", "xeno_vxworks", 0);
 
 	/* Allocate a TSD key for indexing self task pointers. */
 

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1.3: optimise-muxcode-calculation-v4.patch --]
[-- Type: text/x-patch; name="optimise-muxcode-calculation-v4.patch", Size: 7892 bytes --]

---
 include/asm-arm/syscall.h      |   29 ++++++++++++------------
 include/asm-blackfin/syscall.h |    6 +++--
 include/asm-i386/syscall.h     |    7 +++--
 include/asm-ia64/syscall.h     |   25 ++++++++++----------
 include/asm-powerpc/syscall.h  |    7 +++--
 include/nucleus/bind.h         |   19 ++++++++++-----
 src/skins/rtdm/init.c          |   49 +++--------------------------------------
 7 files changed, 56 insertions(+), 86 deletions(-)

Index: xenomai/include/asm-arm/syscall.h
===================================================================
--- xenomai.orig/include/asm-arm/syscall.h
+++ xenomai/include/asm-arm/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #define XENO_ARM_SYSCALL        0x009F0042	/* carefully chosen... */
 
@@ -130,20 +131,20 @@ static inline int __xn_interrupted_p(str
 #define __sys2(x)	#x
 #define __sys1(x)	__sys2(x)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
-  ({								                    \
-        unsigned long __res;					        \
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
+  ({								\
+        unsigned long __res;					\
 	register unsigned long __res_r0 __asm__ ("r0");		\
-   	ASM_INDECL_##nr;					                \
-								                        \
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		    \
-	__asm__ __volatile__ (					            \
-"       swi " __sys1(XENO_ARM_SYSCALL)			        \
-		: "=r" (__res_r0)				                \
-		: ASM_INPUT_##nr				                \
-		: "memory");					                \
-   	__res = __res_r0;					                \
-   	(int) __res;						                \
+   	ASM_INDECL_##nr;					\
+								\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
+	__asm__ __volatile__ (					\
+"       swi " __sys1(XENO_ARM_SYSCALL)				\
+		: "=r" (__res_r0)				\
+		: ASM_INPUT_##nr				\
+		: "memory");					\
+   	__res = __res_r0;					\
+   	(int) __res;						\
   })
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
Index: xenomai/include/asm-blackfin/syscall.h
===================================================================
--- xenomai.orig/include/asm-blackfin/syscall.h
+++ xenomai/include/asm-blackfin/syscall.h
@@ -26,7 +26,8 @@
    marker. Note: watch out for the p0 sign convention used by Linux
    (i.e. negative syscall number in orig_p0 meaning "non-syscall
    entry"). */
-#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) (shifted_id|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) (id << 24)
 
 /* Local syscalls -- the braindamage thing about this arch is the
    absence of atomic ops usable from user-space; so we export what
@@ -213,7 +214,8 @@ static inline int __xn_interrupted_p(str
   __res;								\
 })
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)	__emit_syscall##nr(__xn_mux_code(id,op), ##args)
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...) \
+    __emit_syscall##nr(__xn_mux_code(shifted_id,op), ##args)
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
 #define XENOMAI_SYSCALL1(op,a1)             XENOMAI_DO_SYSCALL(1,0,op,a1)
Index: xenomai/include/asm-i386/syscall.h
===================================================================
--- xenomai.orig/include/asm-i386/syscall.h
+++ xenomai/include/asm-i386/syscall.h
@@ -22,7 +22,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)  ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -165,9 +166,9 @@ asm (".L__X'%ebx = 1\n\t"
     : "i" (__xn_mux_code(0,op)) ASMFMT_##nr(args) : "memory", "cc");  \
     (int) resultvar; })
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...) \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...) \
   ({								      \
-    int muxcode = __xn_mux_code(id,op);                               \
+    int muxcode = __xn_mux_code(shifted_id,op);			      \
     unsigned resultvar;						      \
     asm volatile (						      \
     LOADARGS_##nr						      \
Index: xenomai/include/asm-ia64/syscall.h
===================================================================
--- xenomai.orig/include/asm-ia64/syscall.h
+++ xenomai/include/asm-ia64/syscall.h
@@ -23,7 +23,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|(((id << 16) & 0xff0000UL)|(__xn_sys_mux & 0xffffUL)))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffffUL))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000UL)
 
 #ifdef __KERNEL__
 
@@ -151,17 +152,17 @@ static inline int __xn_interrupted_p(str
   /* Branch registers.  */						\
   "b6", "b7"
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...)                   \
-  ({                                                            \
-    register long _r15 asm ("r15") = (__xn_mux_code(id,op));    \
-    register long _retval asm ("r8");                           \
-    register long err asm ("r10");                              \
-    LOAD_ARGS_##nr (args);                                      \
-    __asm __volatile ("break %3;;\n\t"                          \
-                      : "=r" (_retval), "=r" (_r15), "=r" (err) \
-                      : "i" (__BREAK_SYSCALL), "1" (_r15)       \
-			ASM_ARGS_##nr                           \
-                      : "memory" ASM_CLOBBERS_##nr);            \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...)			\
+  ({									\
+    register long _r15 asm ("r15") = (__xn_mux_code(shifted_id,op));	\
+    register long _retval asm ("r8");					\
+    register long err asm ("r10");					\
+    LOAD_ARGS_##nr (args);						\
+    __asm __volatile ("break %3;;\n\t"					\
+		      : "=r" (_retval), "=r" (_r15), "=r" (err)		\
+		      : "i" (__BREAK_SYSCALL), "1" (_r15)		\
+			ASM_ARGS_##nr					\
+		      : "memory" ASM_CLOBBERS_##nr);			\
     err < 0 ? -_retval : _retval; })
 
 #define XENOMAI_SYS_MUX(nr, op, args...) XENOMAI_SKIN_MUX(nr, 0, op , ##args)
Index: xenomai/include/asm-powerpc/syscall.h
===================================================================
--- xenomai.orig/include/asm-powerpc/syscall.h
+++ xenomai/include/asm-powerpc/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -123,7 +124,7 @@ static inline int __xn_interrupted_p(str
 #define ASM_INPUT_4 ASM_INPUT_3, "4" (__sc_6)
 #define ASM_INPUT_5 ASM_INPUT_4, "5" (__sc_7)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
   ({								\
 	register unsigned long __sc_0  __asm__ ("r0");		\
 	register unsigned long __sc_3  __asm__ ("r3");		\
@@ -132,7 +133,7 @@ static inline int __xn_interrupted_p(str
 	register unsigned long __sc_6  __asm__ ("r6");		\
 	register unsigned long __sc_7  __asm__ ("r7");		\
 								\
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
 	__asm__ __volatile__					\
 		("sc           \n\t"				\
 		 "mfcr %0      "				\

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 249 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Jan Kiszka]

[-- Attachment #1.1: Type: text/plain, Size: 263 bytes --]

Jan Kiszka wrote:
> ...
> Based on this conversion is the optimisation patch -v4. There was
> another quirk hidden in libpthread_rt which binds to RTDM "manually".
> That's now also covered by the patch.

Grr, missing run-quilt-refresh-before-post.

Jan

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1.2: optimise-muxcode-calculation-v4.patch --]
[-- Type: text/x-patch; name="optimise-muxcode-calculation-v4.patch", Size: 8778 bytes --]

---
 include/asm-arm/syscall.h      |   29 +++++++++++++++--------------
 include/asm-blackfin/syscall.h |    6 ++++--
 include/asm-i386/syscall.h     |    7 ++++---
 include/asm-ia64/syscall.h     |   25 +++++++++++++------------
 include/asm-powerpc/syscall.h  |    7 ++++---
 include/nucleus/bind.h         |    2 +-
 src/skins/posix/init.c         |    2 +-
 7 files changed, 42 insertions(+), 36 deletions(-)

Index: xenomai/include/asm-arm/syscall.h
===================================================================
--- xenomai.orig/include/asm-arm/syscall.h
+++ xenomai/include/asm-arm/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)    ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #define XENO_ARM_SYSCALL        0x009F0042	/* carefully chosen... */
 
@@ -130,20 +131,20 @@ static inline int __xn_interrupted_p(str
 #define __sys2(x)	#x
 #define __sys1(x)	__sys2(x)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
-  ({								                    \
-        unsigned long __res;					        \
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
+  ({								\
+        unsigned long __res;					\
 	register unsigned long __res_r0 __asm__ ("r0");		\
-   	ASM_INDECL_##nr;					                \
-								                        \
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		    \
-	__asm__ __volatile__ (					            \
-"       swi " __sys1(XENO_ARM_SYSCALL)			        \
-		: "=r" (__res_r0)				                \
-		: ASM_INPUT_##nr				                \
-		: "memory");					                \
-   	__res = __res_r0;					                \
-   	(int) __res;						                \
+   	ASM_INDECL_##nr;					\
+								\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
+	__asm__ __volatile__ (					\
+"       swi " __sys1(XENO_ARM_SYSCALL)				\
+		: "=r" (__res_r0)				\
+		: ASM_INPUT_##nr				\
+		: "memory");					\
+   	__res = __res_r0;					\
+   	(int) __res;						\
   })
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
Index: xenomai/include/asm-blackfin/syscall.h
===================================================================
--- xenomai.orig/include/asm-blackfin/syscall.h
+++ xenomai/include/asm-blackfin/syscall.h
@@ -26,7 +26,8 @@
    marker. Note: watch out for the p0 sign convention used by Linux
    (i.e. negative syscall number in orig_p0 meaning "non-syscall
    entry"). */
-#define __xn_mux_code(id,op)   ((id << 24)|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) (shifted_id|((op << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) (id << 24)
 
 /* Local syscalls -- the braindamage thing about this arch is the
    absence of atomic ops usable from user-space; so we export what
@@ -213,7 +214,8 @@ static inline int __xn_interrupted_p(str
   __res;								\
 })
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)	__emit_syscall##nr(__xn_mux_code(id,op), ##args)
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...) \
+    __emit_syscall##nr(__xn_mux_code(shifted_id,op), ##args)
 
 #define XENOMAI_SYSCALL0(op)                XENOMAI_DO_SYSCALL(0,0,op)
 #define XENOMAI_SYSCALL1(op,a1)             XENOMAI_DO_SYSCALL(1,0,op,a1)
Index: xenomai/include/asm-i386/syscall.h
===================================================================
--- xenomai.orig/include/asm-i386/syscall.h
+++ xenomai/include/asm-i386/syscall.h
@@ -22,7 +22,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)  ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0x7fff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -165,9 +166,9 @@ asm (".L__X'%ebx = 1\n\t"
     : "i" (__xn_mux_code(0,op)) ASMFMT_##nr(args) : "memory", "cc");  \
     (int) resultvar; })
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...) \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...) \
   ({								      \
-    int muxcode = __xn_mux_code(id,op);                               \
+    int muxcode = __xn_mux_code(shifted_id,op);			      \
     unsigned resultvar;						      \
     asm volatile (						      \
     LOADARGS_##nr						      \
Index: xenomai/include/asm-ia64/syscall.h
===================================================================
--- xenomai.orig/include/asm-ia64/syscall.h
+++ xenomai/include/asm-ia64/syscall.h
@@ -23,7 +23,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|(((id << 16) & 0xff0000UL)|(__xn_sys_mux & 0xffffUL)))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffffUL))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000UL)
 
 #ifdef __KERNEL__
 
@@ -151,17 +152,17 @@ static inline int __xn_interrupted_p(str
   /* Branch registers.  */						\
   "b6", "b7"
 
-#define XENOMAI_SKIN_MUX(nr, id, op, args...)                   \
-  ({                                                            \
-    register long _r15 asm ("r15") = (__xn_mux_code(id,op));    \
-    register long _retval asm ("r8");                           \
-    register long err asm ("r10");                              \
-    LOAD_ARGS_##nr (args);                                      \
-    __asm __volatile ("break %3;;\n\t"                          \
-                      : "=r" (_retval), "=r" (_r15), "=r" (err) \
-                      : "i" (__BREAK_SYSCALL), "1" (_r15)       \
-			ASM_ARGS_##nr                           \
-                      : "memory" ASM_CLOBBERS_##nr);            \
+#define XENOMAI_SKIN_MUX(nr, shifted_id, op, args...)			\
+  ({									\
+    register long _r15 asm ("r15") = (__xn_mux_code(shifted_id,op));	\
+    register long _retval asm ("r8");					\
+    register long err asm ("r10");					\
+    LOAD_ARGS_##nr (args);						\
+    __asm __volatile ("break %3;;\n\t"					\
+		      : "=r" (_retval), "=r" (_r15), "=r" (err)		\
+		      : "i" (__BREAK_SYSCALL), "1" (_r15)		\
+			ASM_ARGS_##nr					\
+		      : "memory" ASM_CLOBBERS_##nr);			\
     err < 0 ? -_retval : _retval; })
 
 #define XENOMAI_SYS_MUX(nr, op, args...) XENOMAI_SKIN_MUX(nr, 0, op , ##args)
Index: xenomai/include/asm-powerpc/syscall.h
===================================================================
--- xenomai.orig/include/asm-powerpc/syscall.h
+++ xenomai/include/asm-powerpc/syscall.h
@@ -25,7 +25,8 @@
 
 #include <asm-generic/xenomai/syscall.h>
 
-#define __xn_mux_code(id,op)        ((op << 24)|((id << 16) & 0xff0000)|(__xn_sys_mux & 0xffff))
+#define __xn_mux_code(shifted_id,op) ((op << 24)|shifted_id|(__xn_sys_mux & 0xffff))
+#define __xn_mux_shifted_id(id) ((id << 16) & 0xff0000)
 
 #ifdef __KERNEL__
 
@@ -123,7 +124,7 @@ static inline int __xn_interrupted_p(str
 #define ASM_INPUT_4 ASM_INPUT_3, "4" (__sc_6)
 #define ASM_INPUT_5 ASM_INPUT_4, "5" (__sc_7)
 
-#define XENOMAI_DO_SYSCALL(nr, id, op, args...)			\
+#define XENOMAI_DO_SYSCALL(nr, shifted_id, op, args...)		\
   ({								\
 	register unsigned long __sc_0  __asm__ ("r0");		\
 	register unsigned long __sc_3  __asm__ ("r3");		\
@@ -132,7 +133,7 @@ static inline int __xn_interrupted_p(str
 	register unsigned long __sc_6  __asm__ ("r6");		\
 	register unsigned long __sc_7  __asm__ ("r7");		\
 								\
-	LOADARGS_##nr(__xn_mux_code(id,op), args);		\
+	LOADARGS_##nr(__xn_mux_code(shifted_id,op), args);	\
 	__asm__ __volatile__					\
 		("sc           \n\t"				\
 		 "mfcr %0      "				\
Index: xenomai/include/nucleus/bind.h
===================================================================
--- xenomai.orig/include/nucleus/bind.h
+++ xenomai/include/nucleus/bind.h
@@ -101,7 +101,7 @@ xeno_user_skin_init(unsigned skin_magic,
     }
 #endif /* !XNSKIN_NO_MLOCK_ALERT */
 
-    return muxid;
+    return __xn_mux_shifted_id(muxid);
 }
 
 #endif /* _XENO_NUCLEUS_BIND_H */
Index: xenomai/src/skins/posix/init.c
===================================================================
--- xenomai.orig/src/skins/posix/init.c
+++ xenomai/src/skins/posix/init.c
@@ -45,7 +45,7 @@ void __init_posix_interface(void)
 	muxid = XENOMAI_SYSBIND(RTDM_SKIN_MAGIC,
 				XENOMAI_FEAT_DEP, XENOMAI_ABI_REV, NULL);
 	if (muxid > 0) {
-		__rtdm_muxid = muxid;
+		__rtdm_muxid = __xn_mux_shifted_id(muxid);
 		__rtdm_fd_start = FD_SETSIZE - XENOMAI_SKINCALL0(__rtdm_muxid,
 								 __rtdm_fdcount);
 	}

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 249 bytes --]

Re: [Xenomai-core] [PATCH] optimise syscall mux-code calculation

[Philippe Gerum]

On Sun, 2006-07-16 at 16:47 +0200, Jan Kiszka wrote:
> Jan Kiszka wrote:
> > ...
> > Based on this conversion is the optimisation patch -v4. There was
> > another quirk hidden in libpthread_rt which binds to RTDM "manually".
> > That's now also covered by the patch.
> 
> Grr, missing run-quilt-refresh-before-post.
> 

Applied, thanks.

> Jan
-- 
Philippe.