Messages in this thread Patch in this message | | | From | kan.liang@intel ... | Subject | [PATCH V2 1/1] perf/x86: filter branches for PEBS event | Date | Fri, 27 Mar 2015 10:38:25 -0400 |
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From: Kan Liang <kan.liang@intel.com>
For supporting Intel LBR branches filtering, Intel LBR sharing logic mechanism is introduced from commit b36817e88630 ("perf/x86: Add Intel LBR sharing logic"). It modifies __intel_shared_reg_get_constraints to config lbr_sel, which is finally used to set LBR_SELECT. However, the intel_shared_regs_constraints is called after intel_pebs_constraints. The PEBS event will return immediately after intel_pebs_constraints. So it's impossible to filter branches for PEBS event.
This patch move intel_shared_regs_constraints ahead of intel_pebs_constraints. We can safely do that because the intel_shared_regs_constraints only returns emptyconstraint if its rejecting the event, otherwise it returns NULL such that we continue calling intel_pebs_constraints and x86_get_event_constraint.
Signed-off-by: Kan Liang <kan.liang@intel.com> ---
Changes since V1: - Move all shared regs ahead of intel_pebs_constraints - Modify the description and quote Peter's comments.
arch/x86/kernel/cpu/perf_event_intel.c | 4 ++-- 1 file 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 9f1dd18..83bee99 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1635,11 +1635,11 @@ intel_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event if (c) return c; - c = intel_pebs_constraints(event); + c = intel_shared_regs_constraints(cpuc, event); if (c) return c; - c = intel_shared_regs_constraints(cpuc, event); + c = intel_pebs_constraints(event); if (c) return c; -- 1.8.3.1
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