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perf_events: Check for filters on fixed counter events

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Intel fixed counters do not support all the filters possible with a
generic counter. Thus, if a fixed counter event is passed but with
certain filters set, then the fixed_mode_idx() function must fail
and the event must be measured in a generic counter instead.

Reject filters are: inv, edge, cnt-mask.

Signed-off-by: Stephane Eranian <eranian@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1254840129-6198-2-git-send-email-eranian@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Stephane Eranian 2009-10-06 16:42:08 +02:00 committed by Ingo Molnar
parent 26dd2cb074
commit 04a705df47
2 changed files with 18 additions and 1 deletions
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13
arch/x86/include/asm/perf_event.h
View File

@ -28,9 +28,20 @@
*/
#define ARCH_PERFMON_EVENT_MASK 0xffff
/*
* filter mask to validate fixed counter events.
* the following filters disqualify for fixed counters:
* - inv
* - edge
* - cnt-mask
* The other filters are supported by fixed counters.
* The any-thread option is supported starting with v3.
*/
#define ARCH_PERFMON_EVENT_FILTER_MASK 0xff840000
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL 0x3c
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK (0x00 << 8)
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX 0
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX 0
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT \
(1 << (ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX))

6
arch/x86/kernel/cpu/perf_event.c
View File

@ -1349,6 +1349,12 @@ fixed_mode_idx(struct perf_event *event, struct hw_perf_event *hwc)
if (!x86_pmu.num_events_fixed)
return -1;
/*
* fixed counters do not take all possible filters
*/
if (hwc->config & ARCH_PERFMON_EVENT_FILTER_MASK)
return -1;
if (unlikely(hw_event == x86_pmu.event_map(PERF_COUNT_HW_INSTRUCTIONS)))
return X86_PMC_IDX_FIXED_INSTRUCTIONS;
if (unlikely(hw_event == x86_pmu.event_map(PERF_COUNT_HW_CPU_CYCLES)))