From: James Clark <james.clark@linaro.org>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Ankur Arora <ankur.a.arora@oracle.com>,
Howard Chu <howardchu95@gmail.com>,
Thomas Falcon <thomas.falcon@intel.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/4] perf off-cpu: Write the sample ID for PERF_SAMPLE_ID
Date: Wed, 28 Oct 2026 09:34:27 +0000 [thread overview]
Message-ID: <418cf6b3-a56d-45e2-b2f6-0c8496e93ea9@linaro.org> (raw)
In-Reply-To: <20261027170415.2815859-2-irogers@google.com>
On 27/10/2026 17:04, Ian Rogers wrote:
> OFFCPU_SAMPLE_TYPES allows PERF_SAMPLE_ID, and the sample ID is
> computed, but off_cpu_write() only wrote it for PERF_SAMPLE_IDENTIFIER.
> When PERF_SAMPLE_ID was set the synthesized samples were one u64 short,
> so the remaining fields were misparsed. Write the ID after the time as
> the sample format requires.
>
> Fixes: edc41a1099c2 ("perf record: Enable off-cpu analysis with BPF")
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/bpf_off_cpu.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
> index ff8935688b43..16948761cc45 100644
> --- a/tools/perf/util/bpf_off_cpu.c
> +++ b/tools/perf/util/bpf_off_cpu.c
> @@ -373,6 +373,8 @@ int off_cpu_write(struct perf_session *session)
> data.array[n++] = 0;
> if (sample_type & PERF_SAMPLE_TIME)
> data.array[n++] = tstamp;
> + if (sample_type & PERF_SAMPLE_ID)
> + data.array[n++] = sid;
> if (sample_type & PERF_SAMPLE_CPU)
> data.array[n++] = 0;
> if (sample_type & PERF_SAMPLE_PERIOD)
Reviewed-by: James Clark <james.clark@linaro.org>
next prev parent reply other threads:[~2026-10-28 9:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-27 17:04 [PATCH v1 1/4] perf off-cpu: Use the CPU map index for the bpf-output file descriptor Ian Rogers
2026-10-27 17:04 ` [PATCH v1 2/4] perf off-cpu: Write the sample ID for PERF_SAMPLE_ID Ian Rogers
2026-10-28 9:34 ` James Clark [this message]
2026-10-27 17:04 ` [PATCH v1 3/4] perf off-cpu: Fix cgroup_filter map sizing Ian Rogers
2026-10-28 9:34 ` James Clark
2026-10-27 17:04 ` [PATCH v1 4/4] libperf evlist: Recompute CPU map when an evsel goes system wide Ian Rogers
2026-10-28 9:35 ` James Clark
2026-10-28 9:34 ` [PATCH v1 1/4] perf off-cpu: Use the CPU map index for the bpf-output file descriptor James Clark
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