[PATCH 1/3] libperf: Add processing to scale the counters obtained during the read() system call when multiplexing

Shunsuke Nakamura
2021-08-20T09:46:41Z

perf_evsel__read() scales counters obtained by RDPMC during multiplexing, but
does not scale counters obtained by read() system call.

Add processing to perf_evsel__read() to scale the counters obtained during the
read() system call when multiplexing.

Signed-off-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
---
tools/lib/perf/evsel.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index d8886720e83d..005cf64a1ad7 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -18,6 +18,7 @@
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <asm/bug.h>
+#include <linux/math64.h>

void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
int idx)
@@ -308,6 +309,9 @@ int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread,
if (readn(FD(evsel, cpu, thread), count->values, size) <= 0)
return -errno;

+ if (count->ena != count->run)
+ count->val = mul_u64_u64_div64(count->val, count->ena, count->run);
+
return 0;
}

--
2.25.1