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Date: Fri, 3 Jan 2014 13:48:04 +0800 From: "Yan, Zheng" <zheng.z.yan@...el.com> To: linux-kernel@...r.kernel.org Cc: a.p.zijlstra@...llo.nl, mingo@...nel.org, acme@...radead.org, eranian@...gle.com, andi@...stfloor.org, "Yan, Zheng" <zheng.z.yan@...el.com> Subject: [PATCH 07/14] perf: track number of events that use LBR callstack Later patch will use it to decide if the LBR stack should be saved/restored Signed-off-by: Yan, Zheng <zheng.z.yan@...el.com> --- arch/x86/kernel/cpu/perf_event_intel_lbr.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index bdd8758..2137a9f 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -201,15 +201,27 @@ void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in) intel_pmu_lbr_reset(); } +static inline bool branch_user_callstack(unsigned br_sel) +{ + return (br_sel & X86_BR_USER) && (br_sel & X86_BR_CALL_STACK); +} + void intel_pmu_lbr_enable(struct perf_event *event) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + struct x86_perf_task_context *task_ctx; if (!x86_pmu.lbr_nr) return; + cpuc = &__get_cpu_var(cpu_hw_events); + task_ctx = event->ctx ? event->ctx->task_ctx_data : NULL; + cpuc->br_sel = event->hw.branch_reg.reg; + if (branch_user_callstack(cpuc->br_sel)) + task_ctx->lbr_callstack_users++; + cpuc->lbr_users++; if (cpuc->lbr_users == 1) perf_sched_cb_enable(event->ctx->pmu); @@ -217,11 +229,18 @@ void intel_pmu_lbr_enable(struct perf_event *event) void intel_pmu_lbr_disable(struct perf_event *event) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + struct cpu_hw_events *cpuc; + struct x86_perf_task_context *task_ctx; if (!x86_pmu.lbr_nr) return; + cpuc = &__get_cpu_var(cpu_hw_events); + task_ctx = event->ctx ? event->ctx->task_ctx_data : NULL; + + if (branch_user_callstack(cpuc->br_sel)) + task_ctx->lbr_callstack_users--; + cpuc->lbr_users--; WARN_ON_ONCE(cpuc->lbr_users < 0); -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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