From: Daniel Axtens <dja@axtens•net>
To: Anshuman Khandual <khandual@linux•vnet.ibm.com>
Cc: linuxppc-dev@ozlabs•org, mikey@neuling•org, sukadev@linux•vnet.ibm.com
Subject: Re: [PATCH V8 08/10] powerpc, perf: Change POWER8 PMU configuration to work with SW filters
Date: Wed, 10 Jun 2015 15:49:25 +1000 [thread overview]
Message-ID: <1433915365.3096.44.camel@axtens.net> (raw)
In-Reply-To: <1433763511-5270-8-git-send-email-khandual@linux.vnet.ibm.com>
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On Mon, 2015-06-08 at 17:08 +0530, Anshuman Khandual wrote:
> The kernel now supports SW based branch filters for book3s systems with
> some specific requirements while dealing with HW supported branch filters
> in order to achieve overall OR semantics prevailing in perf branch stack
> sampling framework. This patch adapts the BHRB branch filter configuration
> to meet those protocols. POWER8 PMU can only handle one HW based branch
> filter request at any point of time. For all other combinations PMU will
> pass it on to the SW.
>
> Signed-off-by: Anshuman Khandual <khandual@linux•vnet.ibm.com>
> ---
> arch/powerpc/perf/power8-pmu.c | 51 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 44 insertions(+), 7 deletions(-)
>
> diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c
> index 5e17cb5..8fccf6c 100644
> --- a/arch/powerpc/perf/power8-pmu.c
> +++ b/arch/powerpc/perf/power8-pmu.c
> @@ -656,6 +656,16 @@ static int power8_generic_events[] = {
>
This is, I think, the third time you've modified this function in this
patch series. I appreciate the fact that you're trying to keep logical
changes separate, but it seems to me like this change might be able to
be combined with patch 4, and given a single commit message that clearly
explains the complete scope of the changes.
> static u64 power8_bhrb_filter_map(u64 branch_sample_type, u64 *bhrb_filter)
> {
> + u64 x, pmu_bhrb_filter;
> +
> + pmu_bhrb_filter = 0;
> + *bhrb_filter = 0;
> +
> + if (branch_sample_type & PERF_SAMPLE_BRANCH_ANY) {
> + *bhrb_filter = PERF_SAMPLE_BRANCH_ANY;
> + return pmu_bhrb_filter;
> + }
> +
> /* BHRB and regular PMU events share the same privilege state
> * filter configuration. BHRB is always recorded along with a
> * regular PMU event. As the privilege state filter is handled
> @@ -666,15 +676,42 @@ static u64 power8_bhrb_filter_map(u64 branch_sample_type, u64 *bhrb_filter)
> /* Ignore user, kernel, hv bits */
> branch_sample_type &= ~PERF_SAMPLE_BRANCH_PLM_ALL;
>
> - /* No branch filter requested */
> - if (branch_sample_type == PERF_SAMPLE_BRANCH_ANY)
> - return 0;
> + /*
> + * POWER8 does not support ORing of PMU HW branch filters. Hence
> + * if multiple branch filters are requested which may include filters
> + * supported in PMU, still go ahead and clear the PMU based HW branch
> + * filter component as in this case all the filters will be processed
> + * in SW.
> + */
>
> - if (branch_sample_type == PERF_SAMPLE_BRANCH_ANY_CALL)
> - return POWER8_MMCRA_IFM1;
> + for_each_branch_sample_type(x) {
> + /* Ignore privilege branch filters */
> + if ((x == PERF_SAMPLE_BRANCH_USER)
> + || (x == PERF_SAMPLE_BRANCH_KERNEL)
> + || (x == PERF_SAMPLE_BRANCH_HV))
> + continue;
> +
> + if (!(branch_sample_type & x))
> + continue;
> +
> + /* Supported individual PMU branch filters */
> + if (branch_sample_type & PERF_SAMPLE_BRANCH_ANY_CALL) {
> + branch_sample_type &= ~PERF_SAMPLE_BRANCH_ANY_CALL;
> + if (branch_sample_type) {
> + /* Multiple filters will be processed in SW */
> + pmu_bhrb_filter = 0;
> + *bhrb_filter = 0;
> + return pmu_bhrb_filter;
> + } else {
> + /* Individual filter will be processed in HW */
> + pmu_bhrb_filter |= POWER8_MMCRA_IFM1;
> + *bhrb_filter |= PERF_SAMPLE_BRANCH_ANY_CALL;
> + return pmu_bhrb_filter;
> + }
> + }
> + }
>
> - /* Every thing else is unsupported */
> - return -1;
> + return pmu_bhrb_filter;
> }
Regards,
Daniel
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next prev parent reply other threads:[~2015-06-10 5:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-08 11:38 [PATCH V8 01/10] powerpc, perf: Drop the branch sample when 'from' cannot be fetched Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 02/10] powerpc, perf: Restore privillege level filter support for BHRB Anshuman Khandual
2015-06-10 3:43 ` Daniel Axtens
2015-06-10 12:08 ` Anshuman Khandual
2015-06-11 3:28 ` Daniel Axtens
2015-06-12 7:06 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 03/10] powerpc, perf: Re organize BHRB processing Anshuman Khandual
2015-06-10 4:36 ` Daniel Axtens
2015-06-10 12:09 ` Anshuman Khandual
2015-06-11 3:32 ` Daniel Axtens
2015-06-12 7:05 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 04/10] powerpc, perf: Re organize PMU based branch filter processing in POWER8 Anshuman Khandual
2015-06-10 5:07 ` Daniel Axtens
2015-06-10 12:09 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 05/10] powerpc, perf: Change the name of HW PMU branch filter tracking variable Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 06/10] powerpc, lib: Add new branch analysis support functions Anshuman Khandual
2015-06-10 5:33 ` Daniel Axtens
2015-06-10 12:10 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 07/10] powerpc, perf: Enable SW filtering in branch stack sampling framework Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 08/10] powerpc, perf: Change POWER8 PMU configuration to work with SW filters Anshuman Khandual
2015-06-10 5:49 ` Daniel Axtens [this message]
2015-06-10 12:10 ` Anshuman Khandual
2015-06-11 3:38 ` Daniel Axtens
2015-06-08 11:38 ` [PATCH V8 09/10] powerpc, perf: Enable privilege mode SW branch filters Anshuman Khandual
2015-06-11 1:19 ` Daniel Axtens
2015-06-12 7:04 ` Anshuman Khandual
2015-06-08 11:38 ` [PATCH V8 10/10] selftests, powerpc: Add test for BHRB branch filters (HW & SW) Anshuman Khandual
2015-06-09 5:41 ` Anshuman Khandual
2015-06-11 2:09 ` Daniel Axtens
2015-06-12 7:02 ` Anshuman Khandual
2015-06-12 7:26 ` Madhavan Srinivasan
2015-06-12 8:59 ` Anshuman Khandual
2015-06-10 3:21 ` [PATCH V8 01/10] powerpc, perf: Drop the branch sample when 'from' cannot be fetched Daniel Axtens
2015-06-10 12:02 ` Anshuman Khandual
2015-06-11 2:22 ` Daniel Axtens
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