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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210820093908.734503-2-nakamura.shun@fujitsu.com>
Date:   Fri, 20 Aug 2021 18:39:06 +0900
From:   Shunsuke Nakamura <nakamura.shun@...itsu.com>
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: [PATCH 1/3] libperf: Add processing to scale the counters obtained during the read() system call when multiplexing

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@...itsu.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