Re: Performance Stats: Kernel patch

[Maxim Uvarov <muvarov@ru.mvista.com>]

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Eric Dumazet wrote:

 >Please check kernel/sys.c:k_getrusage() to see how getrusage() has to 
sum *lot* of individual fields to get precise process numbers (even 
counting stats for dead threads)



Thanks for helping me and for this link. But it is not enough clear for 
me what do you mean at this time.  Inside of patch I am using 2 default 
counters
task_struct->nivcsw and task_struct->nvcsw. And also one new syscall 
counter. And there is only one way to increment this counter, it is from 
entry.S.

If you are speaking about locks,  in my point of view, they are not 
needed in this code. Because increment syscall counter is atomic for X86 
(just one assembly instruction) and in case with PPC (3 instructions) 
there 1) nothing wrong will not happen in any case 2) only own thread 
can increase it's syscall counter. So here should be not any race 
conditions.

I've tested this patch on x86,x86_64,and ppc_32. And I should work now 
with ppc_64 (I didn't check).
And  also updated description.

Best regards,
Maxim Uvarov.

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Patch adds Process Performance Statistics.
It make available to the user the following 
thread performance statistics:
   * Involuntary Context Switches (task_struct->nivcsw)
   * Voluntary Context Switches (task_struct->nvcsw)
   * Number of system calls (added new counter 
     thread_info->sysc_cnt)

Statistics information is available from
/proc/PID/status
   
This data is useful for detecting hyperactivity 
patterns between processes.

Signed-off-by: Maxim Uvarov muvarov@ru.mvista.com

 arch/i386/kernel/asm-offsets.c    |    3 +++
 arch/i386/kernel/entry.S          |    3 +++
 arch/powerpc/kernel/asm-offsets.c |    4 ++++
 arch/powerpc/kernel/entry_32.S    |    5 +++++
 arch/powerpc/kernel/entry_64.S    |    5 +++++
 arch/x86_64/kernel/asm-offsets.c  |    3 +++
 arch/x86_64/kernel/entry.S        |    3 +++
 fs/proc/array.c                   |   17 +++++++++++++++++
 include/asm-i386/thread_info.h    |    5 +++--
 include/asm-powerpc/thread_info.h |    3 +++
 include/asm-x86_64/thread_info.h  |    4 +++-
 kernel/fork.c                     |    4 ++++
 lib/Kconfig.debug                 |   15 +++++++++++++++
 13 files changed, 71 insertions(+), 3 deletions(-)

Index: linux-2.6.21-rc5/fs/proc/array.c
===================================================================
--- linux-2.6.21-rc5.orig/fs/proc/array.c
+++ linux-2.6.21-rc5/fs/proc/array.c
@@ -291,6 +291,20 @@ static inline char *task_cap(struct task
 			    cap_t(p->cap_effective));
 }
 
+#ifdef CONFIG_THREAD_PERF_STAT
+static inline char *task_perf(struct task_struct *p, char *buffer)
+{
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+       buffer += sprintf(buffer, "Syscalls:\t%lu\n", p->thread_info->sysc_cnt);
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
+
+       return buffer + sprintf(buffer, "Nvcsw:\t%lu\n"
+                           "Nivcsw:\t%lu\n",
+                           p->nvcsw,
+                           p->nivcsw);
+}
+#endif /* CONFIG_THREAD_PERF_STAT */
+
 int proc_pid_status(struct task_struct *task, char * buffer)
 {
 	char * orig = buffer;
@@ -309,6 +323,9 @@ int proc_pid_status(struct task_struct *
 #if defined(CONFIG_S390)
 	buffer = task_show_regs(task, buffer);
 #endif
+#ifdef CONFIG_THREAD_PERF_STAT
+	buffer = task_perf(task, buffer);
+#endif /* CONFIG_THREAD_PERF_STAT */
 	return buffer - orig;
 }
 
Index: linux-2.6.21-rc5/kernel/fork.c
===================================================================
--- linux-2.6.21-rc5.orig/kernel/fork.c
+++ linux-2.6.21-rc5/kernel/fork.c
@@ -1044,6 +1044,10 @@ static struct task_struct *copy_process(
 	p->syscr = 0;		/* I/O counter: read syscalls */
 	p->syscw = 0;		/* I/O counter: write syscalls */
 #endif
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+        p->thread_info->sysc_cnt = 0;   /* Syscall counter: total numbers of syscalls */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
+
 	task_io_accounting_init(p);
 	acct_clear_integrals(p);
 
Index: linux-2.6.21-rc5/lib/Kconfig.debug
===================================================================
--- linux-2.6.21-rc5.orig/lib/Kconfig.debug
+++ linux-2.6.21-rc5/lib/Kconfig.debug
@@ -446,3 +446,18 @@ config FAULT_INJECTION_STACKTRACE_FILTER
 	select FRAME_POINTER
 	help
 	  Provide stacktrace filter for fault-injection capabilities
+
+config THREAD_PERF_STAT
+       bool "Per-process (thread) performance statistics"
+       help
+         Make available to the user the following per-process (thread) performance statistics:
+            * Number of involuntary context switches
+            * Number of voluntary context switches
+            * Number of system calls (optional)
+         This information is available via /proc/PID/status.
+
+config THREAD_PERF_STAT_SYSC
+       bool "Enable syscall counter"
+       depends on THREAD_PERF_STAT && (X86 || PPC)
+       help
+         This option adds a syscall counter to /proc/PID/status.
Index: linux-2.6.21-rc5/arch/i386/kernel/entry.S
===================================================================
--- linux-2.6.21-rc5.orig/arch/i386/kernel/entry.S
+++ linux-2.6.21-rc5/arch/i386/kernel/entry.S
@@ -334,6 +334,9 @@ sysenter_past_esp:
 	CFI_ADJUST_CFA_OFFSET 4
 	SAVE_ALL
 	GET_THREAD_INFO(%ebp)
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+        incl    TI_sysc_cnt(%ebp)       # Increment syscalls counter
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 
 	/* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
 	testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
Index: linux-2.6.21-rc5/arch/i386/kernel/asm-offsets.c
===================================================================
--- linux-2.6.21-rc5.orig/arch/i386/kernel/asm-offsets.c
+++ linux-2.6.21-rc5/arch/i386/kernel/asm-offsets.c
@@ -56,6 +56,9 @@ void foo(void)
 	OFFSET(TI_addr_limit, thread_info, addr_limit);
 	OFFSET(TI_restart_block, thread_info, restart_block);
 	OFFSET(TI_sysenter_return, thread_info, sysenter_return);
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+        OFFSET(TI_sysc_cnt, thread_info, sysc_cnt);
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	BLANK();
 
 	OFFSET(GDS_size, Xgt_desc_struct, size);
Index: linux-2.6.21-rc5/include/asm-i386/thread_info.h
===================================================================
--- linux-2.6.21-rc5.orig/include/asm-i386/thread_info.h
+++ linux-2.6.21-rc5/include/asm-i386/thread_info.h
@@ -31,8 +31,9 @@ struct thread_info {
 	unsigned long		status;		/* thread-synchronous flags */
 	__u32			cpu;		/* current CPU */
 	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
-
-
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	unsigned long		sysc_cnt;	/* Syscall counter */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	mm_segment_t		addr_limit;	/* thread address space:
 					 	   0-0xBFFFFFFF for user-thead
 						   0-0xFFFFFFFF for kernel-thread
Index: linux-2.6.21-rc5/arch/powerpc/kernel/asm-offsets.c
===================================================================
--- linux-2.6.21-rc5.orig/arch/powerpc/kernel/asm-offsets.c
+++ linux-2.6.21-rc5/arch/powerpc/kernel/asm-offsets.c
@@ -94,6 +94,10 @@ int main(void)
 	DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
 	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
 	DEFINE(TI_TASK, offsetof(struct thread_info, task));
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+        DEFINE(TI_SYSC_CNT, offsetof(struct thread_info, sysc_cnt));
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
+
 #ifdef CONFIG_PPC32
 	DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
 	DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
Index: linux-2.6.21-rc5/arch/powerpc/kernel/entry_32.S
===================================================================
--- linux-2.6.21-rc5.orig/arch/powerpc/kernel/entry_32.S
+++ linux-2.6.21-rc5/arch/powerpc/kernel/entry_32.S
@@ -202,6 +202,11 @@ _GLOBAL(DoSyscall)
 	bl	do_show_syscall
 #endif /* SHOW_SYSCALLS */
 	rlwinm	r10,r1,0,0,(31-THREAD_SHIFT)	/* current_thread_info() */
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	lwz r11,TI_SYSC_CNT(r10)
+	addi r11,r11,1
+	stw r11,TI_SYSC_CNT(r10)
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	lwz	r11,TI_FLAGS(r10)
 	andi.	r11,r11,_TIF_SYSCALL_T_OR_A
 	bne-	syscall_dotrace
Index: linux-2.6.21-rc5/arch/powerpc/kernel/entry_64.S
===================================================================
--- linux-2.6.21-rc5.orig/arch/powerpc/kernel/entry_64.S
+++ linux-2.6.21-rc5/arch/powerpc/kernel/entry_64.S
@@ -115,6 +115,11 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISER
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 #endif
 	clrrdi	r11,r1,THREAD_SHIFT
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	ld r10,TI_SYSC_CNT(r11)
+	addi r10,r10,1
+	std r10,TI_SYSC_CNT(r11)
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	ld	r10,TI_FLAGS(r11)
 	andi.	r11,r10,_TIF_SYSCALL_T_OR_A
 	bne-	syscall_dotrace
Index: linux-2.6.21-rc5/arch/x86_64/kernel/asm-offsets.c
===================================================================
--- linux-2.6.21-rc5.orig/arch/x86_64/kernel/asm-offsets.c
+++ linux-2.6.21-rc5/arch/x86_64/kernel/asm-offsets.c
@@ -35,6 +35,9 @@ int main(void)
 	ENTRY(addr_limit);
 	ENTRY(preempt_count);
 	ENTRY(status);
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	ENTRY(sysc_cnt);
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	BLANK();
 #undef ENTRY
 #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
Index: linux-2.6.21-rc5/arch/x86_64/kernel/entry.S
===================================================================
--- linux-2.6.21-rc5.orig/arch/x86_64/kernel/entry.S
+++ linux-2.6.21-rc5/arch/x86_64/kernel/entry.S
@@ -229,6 +229,9 @@ ENTRY(system_call)
 	movq  %rcx,RIP-ARGOFFSET(%rsp)
 	CFI_REL_OFFSET rip,RIP-ARGOFFSET
 	GET_THREAD_INFO(%rcx)
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	addq $1, threadinfo_sysc_cnt(%rcx)   # Increment syscalls counter
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%rcx)
 	jnz tracesys
 	cmpq $__NR_syscall_max,%rax
Index: linux-2.6.21-rc5/include/asm-powerpc/thread_info.h
===================================================================
--- linux-2.6.21-rc5.orig/include/asm-powerpc/thread_info.h
+++ linux-2.6.21-rc5/include/asm-powerpc/thread_info.h
@@ -35,6 +35,9 @@ struct thread_info {
 	int		cpu;			/* cpu we're on */
 	int		preempt_count;		/* 0 => preemptable,
 						   <0 => BUG */
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	unsigned long	sysc_cnt;		/* Syscall counter */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	struct restart_block restart_block;
 	unsigned long	local_flags;		/* private flags for thread */
 
Index: linux-2.6.21-rc5/include/asm-x86_64/thread_info.h
===================================================================
--- linux-2.6.21-rc5.orig/include/asm-x86_64/thread_info.h
+++ linux-2.6.21-rc5/include/asm-x86_64/thread_info.h
@@ -30,7 +30,9 @@ struct thread_info {
 	__u32			status;		/* thread synchronous flags */
 	__u32			cpu;		/* current CPU */
 	int 			preempt_count;	/* 0 => preemptable, <0 => BUG */
-
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+	unsigned long		sysc_cnt;	/* Syscall counter */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
 	mm_segment_t		addr_limit;	
 	struct restart_block    restart_block;
 };