linux-kernel - [PATCH] perf test: Fix offcpu test prev

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Message-Id: <20230218162724.1292657-1-namhyung@kernel.org>
Date:   Sat, 18 Feb 2023 08:27:24 -0800
From:   Namhyung Kim <namhyung@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-perf-users@...r.kernel.org
Subject: [PATCH] perf test: Fix offcpu test prev_state check

On Fedora 36, the perf record offcpu profiling tests are failing.
It was because the BPF checks the prev task's state being S or D
but actually it has more bits set.  Let's check the LSB 8 bits
for the purpose of offcpu profiling.

Reported-by: Arnaldo Carvalho de Melo <acme@...nel.org>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 tools/perf/util/bpf_skel/off_cpu.bpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/bpf_skel/off_cpu.bpf.c b/tools/perf/util/bpf_skel/off_cpu.bpf.c
index 38e3b287dbb2..d877a0a9731f 100644
--- a/tools/perf/util/bpf_skel/off_cpu.bpf.c
+++ b/tools/perf/util/bpf_skel/off_cpu.bpf.c
@@ -277,7 +277,7 @@ int on_switch(u64 *ctx)
 	else
 		prev_state = get_task_state(prev);
 
-	return off_cpu_stat(ctx, prev, next, prev_state);
+	return off_cpu_stat(ctx, prev, next, prev_state & 0xff);
 }
 
 char LICENSE[] SEC("license") = "Dual BSD/GPL";
-- 
2.39.2.637.g21b0678d19-goog