* [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
@ 2012-10-31 6:49 Haren Myneni
2012-11-01 0:44 ` Michael Neuling
0 siblings, 1 reply; 5+ messages in thread
From: Haren Myneni @ 2012-10-31 6:49 UTC (permalink / raw)
To: benh, paulus, anton, mikey; +Cc: linuxppc-dev
[PATCH 0/6] powerpc: SMT priority (PPR) save and restore
On P7 systems, users can define SMT priority levels 2,3 and 4 for
processes so that some can run higher priority than the other ones.
In the current kernel, the default priority is set to 4 which prohibits
processes for using higher priority. Also the kernel boosts the priority to
4 during exceptions without saving the user defined priorities when
the task enters the kernel. So we will be loosing the process PPR value
and can not be restored it back when the task exits the kernel.
This patchset implements saving and restore the user defined PPR value
for all tasks.
With null_syscall testcase (http://ozlabs.org/~anton/junkcode/null_syscall.c),
this feature takes around extra 10 CPU cycles on average for 25 samples.
Haren Myneni (6):
powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller
powerpc: Define CPU_FTR_HAS_PPR
powerpc: Increase exceptions arrays in paca struct to save PPR
powerpc: Define ppr in thread_struct
powerpc: Macros for saving/restore PPR
powerpc: Implement PPR save/restore
arch/powerpc/include/asm/cputable.h | 6 ++-
arch/powerpc/include/asm/exception-64s.h | 45 ++++++++++++++++++++++++++----
arch/powerpc/include/asm/paca.h | 6 ++--
arch/powerpc/include/asm/ppc_asm.h | 27 ++++++++++++++++-
arch/powerpc/include/asm/processor.h | 6 ++++
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/entry_64.S | 6 +++-
arch/powerpc/kernel/exceptions-64e.S | 3 +-
arch/powerpc/kernel/exceptions-64s.S | 15 +++++----
arch/powerpc/kernel/process.c | 2 +
11 files changed, 96 insertions(+), 22 deletions(-)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
2012-10-31 6:49 [PATCH 0/6] powerpc: SMT priority (PPR) save and restore Haren Myneni
@ 2012-11-01 0:44 ` Michael Neuling
2012-11-02 1:20 ` Haren Myneni
0 siblings, 1 reply; 5+ messages in thread
From: Michael Neuling @ 2012-11-01 0:44 UTC (permalink / raw)
To: Haren Myneni; +Cc: anton, paulus, linuxppc-dev
Haren Myneni <haren@linux.vnet.ibm.com> wrote:
> [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
>
> On P7 systems, users can define SMT priority levels 2,3 and 4 for
> processes so that some can run higher priority than the other ones.
> In the current kernel, the default priority is set to 4 which prohibits
> processes for using higher priority. Also the kernel boosts the priority to
> 4 during exceptions without saving the user defined priorities when
> the task enters the kernel. So we will be loosing the process PPR value
> and can not be restored it back when the task exits the kernel.
>
> This patchset implements saving and restore the user defined PPR value
> for all tasks.
>
> With null_syscall testcase (http://ozlabs.org/~anton/junkcode/null_syscall.c),
> this feature takes around extra 10 CPU cycles on average for 25 samples.
Haren,
This version doesn't do PPR save/restore over syscall, so is this above
statement still true? null_syscall shouldn't be effected at all, right?
Mikey
>
> Haren Myneni (6):
> powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller
> powerpc: Define CPU_FTR_HAS_PPR
> powerpc: Increase exceptions arrays in paca struct to save PPR
> powerpc: Define ppr in thread_struct
> powerpc: Macros for saving/restore PPR
> powerpc: Implement PPR save/restore
>
> arch/powerpc/include/asm/cputable.h | 6 ++-
> arch/powerpc/include/asm/exception-64s.h | 45 ++++++++++++++++++++++++++----
> arch/powerpc/include/asm/paca.h | 6 ++--
> arch/powerpc/include/asm/ppc_asm.h | 27 ++++++++++++++++-
> arch/powerpc/include/asm/processor.h | 6 ++++
> arch/powerpc/include/asm/reg.h | 1 +
> arch/powerpc/kernel/asm-offsets.c | 1 +
> arch/powerpc/kernel/entry_64.S | 6 +++-
> arch/powerpc/kernel/exceptions-64e.S | 3 +-
> arch/powerpc/kernel/exceptions-64s.S | 15 +++++----
> arch/powerpc/kernel/process.c | 2 +
> 11 files changed, 96 insertions(+), 22 deletions(-)
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
2012-11-01 0:44 ` Michael Neuling
@ 2012-11-02 1:20 ` Haren Myneni
0 siblings, 0 replies; 5+ messages in thread
From: Haren Myneni @ 2012-11-02 1:20 UTC (permalink / raw)
To: Michael Neuling; +Cc: linuxppc-dev, anton, paulus
On 10/31/2012 05:44 PM, Michael Neuling wrote:
> Haren Myneni <haren@linux.vnet.ibm.com> wrote:
>
>> [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
>>
>> On P7 systems, users can define SMT priority levels 2,3 and 4 for
>> processes so that some can run higher priority than the other ones.
>> In the current kernel, the default priority is set to 4 which prohibits
>> processes for using higher priority. Also the kernel boosts the priority to
>> 4 during exceptions without saving the user defined priorities when
>> the task enters the kernel. So we will be loosing the process PPR value
>> and can not be restored it back when the task exits the kernel.
>>
>> This patchset implements saving and restore the user defined PPR value
>> for all tasks.
>>
>> With null_syscall testcase (http://ozlabs.org/~anton/junkcode/null_syscall.c),
>> this feature takes around extra 10 CPU cycles on average for 25 samples.
>
> Haren,
>
> This version doesn't do PPR save/restore over syscall, so is this above
> statement still true? null_syscall shouldn't be effected at all, right?
>
> Mikey
>
Mikey,
Yes this version does not save/ restore for syscall entries. But we set
default priority 3 for each syscall exit - set HMT_MEDIUM_LOW for
normal return, and set 3 in thread.ppr so that this value will be set
for fast return path.
So I was using null_syscall test case to find out the performance
overhead with this patch-set.
Thanks
Haren
>>
>> Haren Myneni (6):
>> powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller
>> powerpc: Define CPU_FTR_HAS_PPR
>> powerpc: Increase exceptions arrays in paca struct to save PPR
>> powerpc: Define ppr in thread_struct
>> powerpc: Macros for saving/restore PPR
>> powerpc: Implement PPR save/restore
>>
>> arch/powerpc/include/asm/cputable.h | 6 ++-
>> arch/powerpc/include/asm/exception-64s.h | 45 ++++++++++++++++++++++++++----
>> arch/powerpc/include/asm/paca.h | 6 ++--
>> arch/powerpc/include/asm/ppc_asm.h | 27 ++++++++++++++++-
>> arch/powerpc/include/asm/processor.h | 6 ++++
>> arch/powerpc/include/asm/reg.h | 1 +
>> arch/powerpc/kernel/asm-offsets.c | 1 +
>> arch/powerpc/kernel/entry_64.S | 6 +++-
>> arch/powerpc/kernel/exceptions-64e.S | 3 +-
>> arch/powerpc/kernel/exceptions-64s.S | 15 +++++----
>> arch/powerpc/kernel/process.c | 2 +
>> 11 files changed, 96 insertions(+), 22 deletions(-)
>>
>>
>>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
@ 2012-12-07 7:44 Haren Myneni
0 siblings, 0 replies; 5+ messages in thread
From: Haren Myneni @ 2012-12-07 7:44 UTC (permalink / raw)
To: benh, paulus, anton, michael.neuling, linuxppc-dev
Ben,
This patch-set is created against your tree (next branch) and fixed the build failure that you pointed.
Changes from the previous version:
- Changes for PPR save/restore in denorm_exception_hv, data_access_slb_relon_pSeries and instruction_access_slb_relon_pSeries
exception vectors (P8) code.
- Fix build failure with ppc64e_defconfig
- Macro name changes (HMT_MEDIUM_PPR_DISCARD and HMT_MEDIUM_PPR_SAVE) and other fixes as Michael Neuling suggested
[PATCH 0/6] powerpc: SMT priority (PPR) save and restore
On P7/P8 systems, users can define SMT priority levels 2,3 and 4 for
processes so that some can run higher priority than the other ones.
In the current kernel, the default priority is set to 4 which prohibits
processes for using higher priority. Also the kernel boosts the priority to
4 during exceptions without saving the user defined priorities when
the task enters the kernel. So we will be loosing the process PPR value
and can not be restored it back when the task exits the kernel.
This patch-set implements saving and restore the user defined PPR value
for all tasks.
With null_syscall testcase (http://ozlabs.org/~anton/junkcode/null_syscall.c),
this feature takes around extra 10 CPU cycles on average for 25 samples.
Haren Myneni (6):
powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller
powerpc: Enable PPR save/restore
powerpc: Increase exceptions arrays in paca struct to save PPR
powerpc: Define ppr in thread_struct
powerpc: Macros for saving/restore PPR
powerpc: Implement PPR save/restore
arch/powerpc/include/asm/cputable.h | 7 +++-
arch/powerpc/include/asm/exception-64s.h | 59 +++++++++++++++++++++++++-----
arch/powerpc/include/asm/paca.h | 6 ++--
arch/powerpc/include/asm/ppc_asm.h | 27 +++++++++++++-
arch/powerpc/include/asm/processor.h | 12 ++++++
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/entry_64.S | 6 +++-
arch/powerpc/kernel/exceptions-64e.S | 3 +-
arch/powerpc/kernel/exceptions-64s.S | 23 +++++++-----
arch/powerpc/kernel/process.c | 2 +
11 files changed, 119 insertions(+), 28 deletions(-)
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 0/6] powerpc: SMT priority (PPR) save and restore
@ 2012-09-09 11:32 Haren Myneni
0 siblings, 0 replies; 5+ messages in thread
From: Haren Myneni @ 2012-09-09 11:32 UTC (permalink / raw)
To: benh, paulus, anton, mikey; +Cc: linuxppc-dev
On P7 systems, users can define SMT priority levels 2,3 and 4 for
processes so that some can run higher priority than the other ones.
In the current kernel, the default priority is set to 4 which prohibits
processes for using higher priority. Also the kernel boosts the priority to
4 during exceptions without saving the user defined priorities when
the task enters the kernel. So we will be loosing the process PPR value
and can not be restored it back when the task exits the kernel.
This patch set implements saving and restore the user defined PPR value
for all tasks.
Haren Myneni (6):
powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller
powerpc: Add enable_ppr kernel parameter to enable PPR save/restore
powerpc: Add ppr in thread_info struct
powerpc: Increase exceptions arrays in paca struct to save PPR
powerpc: Macros for saving/restore PPR
powerpc: Implement PPR save/restore
Documentation/kernel-parameters.txt | 4 +++
arch/powerpc/include/asm/cputable.h | 6 ++--
arch/powerpc/include/asm/exception-64s.h | 51 ++++++++++++++++++++++++++----
arch/powerpc/include/asm/paca.h | 6 ++--
arch/powerpc/include/asm/ppc_asm.h | 2 --
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/include/asm/thread_info.h | 11 +++++++
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/entry_64.S | 7 +++-
arch/powerpc/kernel/exceptions-64s.S | 18 ++++++-----
arch/powerpc/kernel/setup_64.c | 14 ++++++++
11 files changed, 99 insertions(+), 22 deletions(-)
--
1.7.10.4
^ permalink raw reply [flat|nested] 5+ messages in thread
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2012-10-31 6:49 [PATCH 0/6] powerpc: SMT priority (PPR) save and restore Haren Myneni
2012-11-01 0:44 ` Michael Neuling
2012-11-02 1:20 ` Haren Myneni
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2012-12-07 7:44 Haren Myneni
2012-09-09 11:32 Haren Myneni
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