From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH v3 3/4] perf record: Don't clear event's period if set by a term
Date: Mon, 14 Sep 2020 18:51:06 -0300 [thread overview]
Message-ID: <20200914215106.GF166601@kernel.org> (raw)
In-Reply-To: <20200914214655.GE166601@kernel.org>
Em Mon, Sep 14, 2020 at 06:46:55PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Sep 11, 2020 at 07:56:54PM -0700, Ian Rogers escreveu:
> > If events in a group explicitly set a frequency or period with leader
> > sampling, don't disable the samples on those events.
> >
> > Prior to 5.8:
> > perf record -e '{cycles/period=12345000/,instructions/period=6789000/}:S'
> > would clear the attributes then apply the config terms. In commit
> > 5f34278867b7 leader sampling configuration was moved to after applying the
> > config terms, in the example, making the instructions' event have its period
> > cleared.
> > This change makes it so that sampling is only disabled if configuration
> > terms aren't present.
>
> Adrian, Jiri, can you please take a look a this and provide Reviewed-by
> or Acked-by tags?
Without this patch we have:
# perf record -e '{cycles/period=1/,instructions/period=2/}:S' sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.051 MB perf.data (6 samples) ]
#
# perf evlist -v
cycles/period=1/: size: 120, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, disabled: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
instructions/period=2/: size: 120, config: 0x1, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, sample_id_all: 1, exclude_guest: 1
#
So indeed the period=2 is being cleared for the second event in that
group.
- Arnaldo
next prev parent reply other threads:[~2020-09-14 21:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-12 2:56 [PATCH v3 0/4] Fixes for setting event freq/periods Ian Rogers
2020-09-12 2:56 ` [PATCH v3 1/4] perf record: Set PERF_RECORD_PERIOD if attr->freq is set Ian Rogers
2020-09-12 2:56 ` [PATCH v3 2/4] perf record: Prevent override of attr->sample_period for libpfm4 events Ian Rogers
2020-09-12 2:56 ` [PATCH v3 3/4] perf record: Don't clear event's period if set by a term Ian Rogers
2020-09-14 6:02 ` Adrian Hunter
2020-09-14 21:46 ` Arnaldo Carvalho de Melo
2020-09-14 21:51 ` Arnaldo Carvalho de Melo [this message]
2020-09-14 21:52 ` Ian Rogers
2020-09-14 22:34 ` Arnaldo Carvalho de Melo
2020-09-12 2:56 ` [PATCH v3 4/4] perf test: Leader sampling shouldn't clear sample period Ian Rogers
2020-09-14 22:36 ` Arnaldo Carvalho de Melo
2020-09-12 20:49 ` [PATCH v3 0/4] Fixes for setting event freq/periods Jiri Olsa
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