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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-04-26 11:24:33 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-26 11:34:34 (GMT) |
| commit | 18a073a3acd3a47fbb5e23333df7fad28d576345 (patch) | |
| tree | 7b961ab5fd0f98a2348e4eaa419838040d7f8034 /arch/x86 | |
| parent | cd2e49e90f1cae7726c9a2c54488d881d7f1cd1c (diff) | |
| download | linux-18a073a3acd3a47fbb5e23333df7fad28d576345.tar.xz | |
perf, x86: Fix BTS condition
Currently the x86 backend incorrectly assumes that any BRANCH_INSN
with sample_period==1 is a BTS request. This is not true when we do
frequency driven profiling such as 'perf record -e branches'.
Solves this error:
$ perf record -e branches ./array
Error: sys_perf_event_open() syscall returned with 95 (Operation not supported).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: "Metzger, Markus T" <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-rd2y4ct71hjawzz6fpvsy9hg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel.c | 3 |
2 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 632e5dc..fac0654 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -613,8 +613,8 @@ static int x86_setup_perfctr(struct perf_event *event) /* * Branch tracing: */ - if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) && - (hwc->sample_period == 1)) { + if (attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS && + !attr->freq && hwc->sample_period == 1) { /* BTS is not supported by this architecture. */ if (!x86_pmu.bts_active) return -EOPNOTSUPP; diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 43fa20b..9194b06 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -998,6 +998,9 @@ intel_bts_constraints(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; unsigned int hw_event, bts_event; + if (event->attr.freq) + return NULL; + hw_event = hwc->config & INTEL_ARCH_EVENT_MASK; bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS); |