linux-kernel - [PATCH 09/15] perf: Track system-wide LBR users and LBR callstack users

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Date:	Wed, 11 Dec 2013 15:10:54 +0800
From:	"Yan, Zheng" <zheng.z.yan@...el.com>
To:	linux-kernel@...r.kernel.org
Cc:	a.p.zijlstra@...llo.nl, eranian@...gle.com, andi@...stfloor.org,
	"Yan, Zheng" <zheng.z.yan@...el.com>
Subject: [PATCH 09/15] perf: Track system-wide LBR users and LBR callstack users

From: "Yan, Zheng" <zheng.z.yan@...el.com>

Signed-off-by: Yan, Zheng <zheng.z.yan@...el.com>
---
 arch/x86/kernel/cpu/perf_event.h           |  1 +
 arch/x86/kernel/cpu/perf_event_intel_lbr.c | 25 ++++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 3ed9629..bcc8e1f 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -150,6 +150,7 @@ struct cpu_hw_events {
 	 * Intel LBR bits
 	 */
 	int				lbr_users;
+	int				lbr_sys_users;
 	struct perf_branch_stack	lbr_stack;
 	struct perf_branch_entry	lbr_entries[MAX_LBR_ENTRIES];
 	struct er_account		*lbr_sel;
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index c33bf84c..f57960d 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -201,15 +201,29 @@ 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 (!(event->attach_state & PERF_ATTACH_TASK))
+		cpuc->lbr_sys_users++;
+	else 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 +231,20 @@ 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 (!(event->attach_state & PERF_ATTACH_TASK))
+		cpuc->lbr_sys_users--;
+	else if (branch_user_callstack(cpuc->br_sel))
+		task_ctx->lbr_callstack_users--;
+
 	cpuc->lbr_users--;
 	WARN_ON_ONCE(cpuc->lbr_users < 0);
 
-- 
1.8.1.4

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