linux-kernel - [PATCH 3/3] x86, perf: Trace rdpmc too

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Date:	Thu, 19 Mar 2015 17:29:29 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, peterz@...radead.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 3/3] x86, perf: Trace rdpmc too

From: Andi Kleen <ak@...ux.intel.com>

perf uses RDPMC to read the performance counters, so it's useful to trace
that too. Add a trace point for RDPMC too, similar to the existing
MSR ones. Since there is only a single call of rdpmc in the whole kernel
(in perf)
just add the trace statement to that call, instead of moving the rdpmcl
inline out of line.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/kernel/cpu/perf_event.c | 3 +++
 include/trace/events/msr.h       | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e0dab5c..9644d95 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -26,6 +26,8 @@
 #include <linux/bitops.h>
 #include <linux/device.h>
 
+#include <trace/events/msr.h>
+
 #include <asm/apic.h>
 #include <asm/stacktrace.h>
 #include <asm/nmi.h>
@@ -82,6 +84,7 @@ u64 x86_perf_event_update(struct perf_event *event)
 again:
 	prev_raw_count = local64_read(&hwc->prev_count);
 	rdpmcl(hwc->event_base_rdpmc, new_raw_count);
+	trace_rdpmc(hwc->event_base_rdpmc, new_raw_count, 0);
 
 	if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
 					new_raw_count) != prev_raw_count)
diff --git a/include/trace/events/msr.h b/include/trace/events/msr.h
index e1677e8..4fa81b5 100644
--- a/include/trace/events/msr.h
+++ b/include/trace/events/msr.h
@@ -40,6 +40,12 @@ DEFINE_EVENT(msr_trace_class, write_msr,
 	     TP_ARGS(msr, val, failed)
 );
 
+DEFINE_EVENT(msr_trace_class, rdpmc,
+	     TP_PROTO(unsigned msr, u64 val, int failed),
+	     TP_ARGS(msr, val, failed)
+);
+
+
 #endif /* _TRACE_MSR_H */
 
 /* This part must be outside protection */
-- 
1.9.3

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