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

Andi Kleen
2015-03-20T00:29:38Z

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@linux.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