diff options
author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-03-03 13:12:23 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2010-03-10 13:23:32 +0100 |
commit | ef21f683a045a79b6aa86ad81e5fdfc0d5ddd250 (patch) | |
tree | ccf39f5051608c1eccac9171259c2d7bc381cc96 /arch/x86/kernel/cpu/perf_event_intel.c | |
parent | caff2befffe899e63df5cc760b7ed01cfd902685 (diff) |
perf, x86: use LBR for PEBS IP+1 fixup
Use the LBR to fix up the PEBS IP+1 issue.
As said, PEBS reports the next instruction, here we use the LBR to find
the last branch and from that construct the actual IP. If the IP matches
the LBR-TO, we use LBR-FROM, otherwise we use the LBR-TO address as the
beginning of the last basic block and decode forward.
Once we find a match to the current IP, we use the previous location.
This patch introduces a new ABI element: PERF_RECORD_MISC_EXACT, which
conveys that the reported IP (PERF_SAMPLE_IP) is the exact instruction
that caused the event (barring CPU errata).
The fixup can fail due to various reasons:
1) LBR contains invalid data (quite possible)
2) part of the basic block got paged out
3) the reported IP isn't part of the basic block (see 1)
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <20100304140100.619375431@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel.c')
-rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 44f6ed42a934..7eb78be3b229 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -547,7 +547,7 @@ static void intel_pmu_disable_event(struct perf_event *event) x86_pmu_disable_event(event); if (unlikely(event->attr.precise)) - intel_pmu_pebs_disable(hwc); + intel_pmu_pebs_disable(event); } static void intel_pmu_enable_fixed(struct hw_perf_event *hwc) @@ -600,7 +600,7 @@ static void intel_pmu_enable_event(struct perf_event *event) } if (unlikely(event->attr.precise)) - intel_pmu_pebs_enable(hwc); + intel_pmu_pebs_enable(event); __x86_pmu_enable_event(hwc); } |