* [PATCH v3] perf: honoring the architectural performance monitoring version
@ 2015-06-15 14:22 Imre Palik
2015-06-16 9:21 ` Peter Zijlstra
0 siblings, 1 reply; 3+ messages in thread
From: Imre Palik @ 2015-06-15 14:22 UTC (permalink / raw)
To: Peter Zijlstra, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
Cc: Thomas Gleixner, H. Peter Anvin, x86, linux-kernel, Palik, Imre,
Anthony Liguori
From: "Palik, Imre" <imrep@amazon.de>
Architectural performance monitoring version 1 doesn't support fixed
counters. Currently, even if a hypervisor advertises support for
architectural performance monitoring version 1, perf may still tries to use
the fixed counters, as the constraints are set up based on the CPU model.
This patch ensures that perf honors the architectural performance
monitoring version returned by CPUID, and it only uses the fixed counters
for version two and above.
Some of the ideas in this patch are coming from Peter Zijlstra.
Signed-off-by: Imre Palik <imrep@amazon.de>
Cc: Anthony Liguori <aliguori@amazon.com>
---
arch/x86/kernel/cpu/perf_event_intel.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index a1e35c9..c54bb97 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -3322,13 +3322,14 @@ __init int intel_pmu_init(void)
* counter, so do not extend mask to generic counters
*/
for_each_event_constraint(c, x86_pmu.event_constraints) {
- if (c->cmask != FIXED_EVENT_FLAGS
- || c->idxmsk64 == INTEL_PMC_MSK_FIXED_REF_CYCLES) {
- continue;
+ if (c->cmask == FIXED_EVENT_FLAGS
+ && c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) {
+ c->idxmsk64 |=
+ (1ULL << x86_pmu.num_counters) - 1;
}
-
- c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
- c->weight += x86_pmu.num_counters;
+ c->idxmsk64 &=
+ ~(~0UL << (INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed));
+ c->weight = hweight64(c->idxmsk64);
}
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3] perf: honoring the architectural performance monitoring version
2015-06-15 14:22 [PATCH v3] perf: honoring the architectural performance monitoring version Imre Palik
@ 2015-06-16 9:21 ` Peter Zijlstra
2015-06-18 14:25 ` Imre Palik
0 siblings, 1 reply; 3+ messages in thread
From: Peter Zijlstra @ 2015-06-16 9:21 UTC (permalink / raw)
To: Imre Palik
Cc: Paul Mackerras, Ingo Molnar, Arnaldo Carvalho de Melo,
Thomas Gleixner, H. Peter Anvin, x86, linux-kernel, Palik, Imre,
Anthony Liguori
On Mon, Jun 15, 2015 at 04:22:32PM +0200, Imre Palik wrote:
> From: "Palik, Imre" <imrep@amazon.de>
>
> Architectural performance monitoring version 1 doesn't support fixed
> counters. Currently, even if a hypervisor advertises support for
> architectural performance monitoring version 1, perf may still tries to use
> the fixed counters, as the constraints are set up based on the CPU model.
>
> This patch ensures that perf honors the architectural performance
> monitoring version returned by CPUID, and it only uses the fixed counters
> for version two and above.
>
> Some of the ideas in this patch are coming from Peter Zijlstra.
What's the difference from -v2? I'm not really seeing it.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] perf: honoring the architectural performance monitoring version
2015-06-16 9:21 ` Peter Zijlstra
@ 2015-06-18 14:25 ` Imre Palik
0 siblings, 0 replies; 3+ messages in thread
From: Imre Palik @ 2015-06-18 14:25 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Paul Mackerras, Ingo Molnar, Arnaldo Carvalho de Melo,
Thomas Gleixner, H. Peter Anvin, x86, linux-kernel, Palik, Imre,
Anthony Liguori
On 06/16/15 11:21, Peter Zijlstra wrote:
> On Mon, Jun 15, 2015 at 04:22:32PM +0200, Imre Palik wrote:
>> From: "Palik, Imre" <imrep@amazon.de>
>>
>> Architectural performance monitoring version 1 doesn't support fixed
>> counters. Currently, even if a hypervisor advertises support for
>> architectural performance monitoring version 1, perf may still tries to use
>> the fixed counters, as the constraints are set up based on the CPU model.
>>
>> This patch ensures that perf honors the architectural performance
>> monitoring version returned by CPUID, and it only uses the fixed counters
>> for version two and above.
>>
>> Some of the ideas in this patch are coming from Peter Zijlstra.
>
> What's the difference from -v2? I'm not really seeing it.
>
I made the mistake of sending two different versions as v2. v3 is the same
as the second v2.
I sent this to clear up possible confusion. Sorry if it caused more of it.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-06-15 14:22 [PATCH v3] perf: honoring the architectural performance monitoring version Imre Palik
2015-06-16 9:21 ` Peter Zijlstra
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