Messages in this thread | | | Date | Wed, 24 Oct 2012 16:23:16 +0800 | From | "Yan, Zheng" <> | Subject | Re: [PATCH V2 1/7] perf, x86: Reduce lbr_sel_map size |
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On 10/24/2012 04:15 PM, Stephane Eranian wrote: > On Wed, Oct 24, 2012 at 9:49 AM, Yan, Zheng <zheng.z.yan@intel.com> wrote: >> On 10/24/2012 03:28 PM, Stephane Eranian wrote: >>> On Wed, Oct 24, 2012 at 7:59 AM, Yan, Zheng <zheng.z.yan@intel.com> wrote: >>>> From: "Yan, Zheng" <zheng.z.yan@intel.com> >>>> >>>> The index of lbr_sel_map is bit value of perf branch_sample_type. >>>> By using bit shift as index, we can reduce lbr_sel_map size. >>>> >>>> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> >>>> --- >>>> arch/x86/kernel/cpu/perf_event.h | 4 +++ >>>> arch/x86/kernel/cpu/perf_event_intel_lbr.c | 50 ++++++++++++++---------------- >>>> include/uapi/linux/perf_event.h | 42 +++++++++++++++++-------- >>>> 3 files changed, 56 insertions(+), 40 deletions(-) >>>> >>>> diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h >>>> index d3b3bb7..ea6749a 100644 >>>> --- a/arch/x86/kernel/cpu/perf_event.h >>>> +++ b/arch/x86/kernel/cpu/perf_event.h >>>> @@ -412,6 +412,10 @@ struct x86_pmu { >>>> struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr); >>>> }; >>>> >>>> +enum { >>>> + PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE = PERF_SAMPLE_BRANCH_MAX_SHIFT, >>>> +}; >>>> + >>> What's the point on the extraneous definition? >> >> because later patches will add map PERF_SAMPLE_BRANCH_CALL_STACK, it will make >> "PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE != PERF_SAMPLE_BRANCH_MAX_SHIFT" >> > And you are not going to do: > > enum perf_branch_sample_type_shift { > ... > PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT = 10 > PERF_SAMPLE_BRANCH_MAX_SHIFT > }; > > PERF_SAMPLE_BRANCH_CALL_STACK = 1 << PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT > > Unless you're telling you are not going to add a mapping for > PERF_SAMPLE_CALL_STACK to the > lbr_sel_map[]? >
I think include/uapi/linux/perf_event.h should only contain definition for user API. So I added PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT and PERF_SAMPLE_BRANCH_CALL_STACK to arch/x86/kernel/cpu/perf_event.h. Please check patch 1.
Regards Yan, Zheng
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