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Message-ID: <20191021115546.GA5845@krava>
Date: Mon, 21 Oct 2019 13:55:46 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Jiwei Sun <Jiwei.Sun@...driver.com>
Cc: acme@...hat.com, arnaldo.melo@...il.com,
linux-kernel@...r.kernel.org, alexander.shishkin@...ux.intel.com,
mpetlan@...hat.com, namhyung@...nel.org, a.p.zijlstra@...llo.nl,
adrian.hunter@...el.com, Richard.Danter@...driver.com
Subject: Re: [PATCH v4] perf record: Add support for limit perf output file
size
On Mon, Oct 21, 2019 at 07:51:17PM +0800, Jiwei Sun wrote:
> Hello Arnaldo & Jirka,
>
> Do you have any other suggestions regarding the patch?
> Any suggestions are welcome. Thank you very much.
oops, overlooked this one, sry.. I'll check on it today
jirka
>
> Regards,
> Jiwei
>
> On 2019e9409f..25f.% 15:06, Jiwei Sun wrote:
> > The patch adds a new option to limit the output file size, then based
> > on it, we can create a wrapper of the perf command that uses the option
> > to avoid exhausting the disk space by the unconscious user.
> >
> > In order to make the perf.data parsable, we just limit the sample data
> > size, since the perf.data consists of many headers and sample data and
> > other data, the actual size of the recorded file will bigger than the
> > setting value.
> >
> > Testing it:
> >
> > # ./perf record -a -g --max-size=10M
> > Couldn't synthesize bpf events.
> > WARNING: The perf data has already reached the limit, stop recording!
> > [ perf record: Woken up 30 times to write data ]
> > [ perf record: Captured and wrote 10.233 MB perf.data (175650 samples) ]
> > Terminated
> >
> > # ls -lh perf.data
> > -rw------- 1 root root 11M Jul 17 14:01 perf.data
> >
> > # ./perf record -a -g --max-size=10K
> > WARNING: The perf data has already reached the limit, stop recording!
> > Couldn't synthesize bpf events.
> > [ perf record: Woken up 0 times to write data ]
> > [ perf record: Captured and wrote 1.824 MB perf.data (67 samples) ]
> > Terminated
> >
> > # ls -lh perf.data
> > -rw------- 1 root root 1.9M Jul 17 14:05 perf.data
> >
> > Signed-off-by: Jiwei Sun <jiwei.sun@...driver.com>
> > ---
> > v4 changes:
> > - Just show one WARNING message after reached the limit.
> >
> > v3 changes:
> > - add a test result
> > - add the new option to tools/perf/Documentation/perf-record.txt
> >
> > v2 changes:
> > - make patch based on latest Arnaldo's perf/core,
> > - display warning message when reached the limit.
> > ---
> > tools/perf/Documentation/perf-record.txt | 4 +++
> > tools/perf/builtin-record.c | 42 ++++++++++++++++++++++++
> > 2 files changed, 46 insertions(+)
> >
> > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> > index c6f9f31b6039..f1c6113fbc82 100644
> > --- a/tools/perf/Documentation/perf-record.txt
> > +++ b/tools/perf/Documentation/perf-record.txt
> > @@ -571,6 +571,10 @@ config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
> >
> > Implies --tail-synthesize.
> >
> > +--max-size=<size>::
> > +Limit the sample data max size, <size> is expected to be a number with
> > +appended unit character - B/K/M/G
> > +
> > SEE ALSO
> > --------
> > linkperf:perf-stat[1], linkperf:perf-list[1]
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index 48600c90cc7e..30904d2a3407 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -91,6 +91,7 @@ struct record {
> > struct switch_output switch_output;
> > unsigned long long samples;
> > cpu_set_t affinity_mask;
> > + unsigned long output_max_size; /* = 0: unlimited */
> > };
> >
> > static volatile int auxtrace_record__snapshot_started;
> > @@ -120,6 +121,12 @@ static bool switch_output_time(struct record *rec)
> > trigger_is_ready(&switch_output_trigger);
> > }
> >
> > +static bool record__output_max_size_exceeded(struct record *rec)
> > +{
> > + return rec->output_max_size &&
> > + (rec->bytes_written >= rec->output_max_size);
> > +}
> > +
> > static int record__write(struct record *rec, struct mmap *map __maybe_unused,
> > void *bf, size_t size)
> > {
> > @@ -132,6 +139,12 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused,
> >
> > rec->bytes_written += size;
> >
> > + if (record__output_max_size_exceeded(rec)) {
> > + WARN_ONCE(1, "WARNING: The perf data has already reached "
> > + "the limit, stop recording!\n");
> > + raise(SIGTERM);
> > + }
> > +
> > if (switch_output_size(rec))
> > trigger_hit(&switch_output_trigger);
> >
> > @@ -1936,6 +1949,33 @@ static int record__parse_affinity(const struct option *opt, const char *str, int
> > return 0;
> > }
> >
> > +static int parse_output_max_size(const struct option *opt,
> > + const char *str, int unset)
> > +{
> > + unsigned long *s = (unsigned long *)opt->value;
> > + static struct parse_tag tags_size[] = {
> > + { .tag = 'B', .mult = 1 },
> > + { .tag = 'K', .mult = 1 << 10 },
> > + { .tag = 'M', .mult = 1 << 20 },
> > + { .tag = 'G', .mult = 1 << 30 },
> > + { .tag = 0 },
> > + };
> > + unsigned long val;
> > +
> > + if (unset) {
> > + *s = 0;
> > + return 0;
> > + }
> > +
> > + val = parse_tag_value(str, tags_size);
> > + if (val != (unsigned long) -1) {
> > + *s = val;
> > + return 0;
> > + }
> > +
> > + return -1;
> > +}
> > +
> > static int record__parse_mmap_pages(const struct option *opt,
> > const char *str,
> > int unset __maybe_unused)
> > @@ -2262,6 +2302,8 @@ static struct option __record_options[] = {
> > "n", "Compressed records using specified level (default: 1 - fastest compression, 22 - greatest compression)",
> > record__parse_comp_level),
> > #endif
> > + OPT_CALLBACK(0, "max-size", &record.output_max_size,
> > + "size", "Limit the maximum size of the output file", parse_output_max_size),
> > OPT_END()
> > };
> >
> >
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