Messages in this thread | | | Subject | Re: [PATCH v1] perf record: Add an option to take an AUX snapshot on exit | From | Adrian Hunter <> | Date | Wed, 7 Aug 2019 10:40:39 +0300 |
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On 6/08/19 5:41 PM, Alexander Shishkin wrote: > It is sometimes useful to generate a snapshot when perf record exits; > I've been using a wrapper script around the workload that would do a > killall -USR2 perf when the workload exits. > > This patch makes it easier and also works when perf record is attached > to a pre-existing task. A new snapshot option 'e' can be specified in > -S to enable this behavior: > > root@elsewhere:~# perf record -e intel_pt// -Se sleep 1 > [ perf record: Woken up 2 times to write data ] > [ perf record: Captured and wrote 0.085 MB perf.data ] > > Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> > Co-developed-by: Adrian Hunter <adrian.hunter@intel.com>
checkpatch says: WARNING: Co-developed-by: must be immediately followed by Signed-off-by
> --- > tools/perf/Documentation/perf-record.txt | 11 +++++--- > tools/perf/builtin-record.c | 34 +++++++++++++++++++++--- > tools/perf/perf.h | 1 + > tools/perf/util/auxtrace.c | 14 ++++++++-- > tools/perf/util/auxtrace.h | 2 +- > 5 files changed, 52 insertions(+), 10 deletions(-) > > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 15e0fa87241b..d5e58e0a2bca 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -422,9 +422,14 @@ CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI. > -S:: > --snapshot:: > Select AUX area tracing Snapshot Mode. This option is valid only with an > -AUX area tracing event. Optionally the number of bytes to capture per > -snapshot can be specified. In Snapshot Mode, trace data is captured only when > -signal SIGUSR2 is received. > +AUX area tracing event. Optionally, certain snapshot capturing parameters > +can be specified in a string that follows this option: > + 'e': take one last snapshot on exit; guarantees that there is at least one > + snapshot in the output file; > + <size>: if the PMU supports this, specify the desired snapshot size. > + > +In Snapshot Mode trace data is captured only when signal SIGUSR2 is received > +and on exit if the above 'e' option is given. > > --proc-map-timeout:: > When processing pre-existing threads /proc/XXX/mmap, it may take a long time, > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index d31d7a5a1be3..e9a2525ecfcc 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -613,19 +613,35 @@ static int record__auxtrace_read_snapshot_all(struct record *rec) > return rc; > } > > -static void record__read_auxtrace_snapshot(struct record *rec) > +static void record__read_auxtrace_snapshot(struct record *rec, bool on_exit) > { > pr_debug("Recording AUX area tracing snapshot\n"); > if (record__auxtrace_read_snapshot_all(rec) < 0) { > trigger_error(&auxtrace_snapshot_trigger); > } else { > - if (auxtrace_record__snapshot_finish(rec->itr)) > + if (auxtrace_record__snapshot_finish(rec->itr, on_exit)) > trigger_error(&auxtrace_snapshot_trigger); > else > trigger_ready(&auxtrace_snapshot_trigger); > } > } > > +static int record__auxtrace_snapshot_exit(struct record *rec) > +{ > + if (trigger_is_error(&auxtrace_snapshot_trigger)) > + return 0; > + > + if (!auxtrace_record__snapshot_started && > + auxtrace_record__snapshot_start(rec->itr)) > + return -1; > + > + record__read_auxtrace_snapshot(rec, true);
Buffers can get un-mapped earlier as tasks exit. Refer perf_evlist__filter_pollfd() -> perf_evlist__munmap_filtered(). Maybe we should prevent that for this case. e.g. do perf_mmap__get()'s on the mmaps at the start, and then 'put' them all here.
> + if (trigger_is_error(&auxtrace_snapshot_trigger)) > + return -1; > + > + return 0; > +} > + > static int record__auxtrace_init(struct record *rec) > { > int err; > @@ -654,7 +670,7 @@ int record__auxtrace_mmap_read(struct record *rec __maybe_unused, > } > > static inline > -void record__read_auxtrace_snapshot(struct record *rec __maybe_unused) > +void record__read_auxtrace_snapshot(struct record *rec __maybe_unused, bool on_exit) > { > } > > @@ -664,6 +680,12 @@ int auxtrace_record__snapshot_start(struct auxtrace_record *itr __maybe_unused) > return 0; > } > > +static inline > +int record__auxtrace_snapshot_exit(struct record *rec) > +{ > + return 0; > +} > + > static int record__auxtrace_init(struct record *rec __maybe_unused) > { > return 0; > @@ -1536,7 +1558,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) > if (auxtrace_record__snapshot_started) { > auxtrace_record__snapshot_started = 0; > if (!trigger_is_error(&auxtrace_snapshot_trigger)) > - record__read_auxtrace_snapshot(rec); > + record__read_auxtrace_snapshot(rec, false); > if (trigger_is_error(&auxtrace_snapshot_trigger)) { > pr_err("AUX area tracing snapshot failed\n"); > err = -1; > @@ -1609,9 +1631,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) > disabled = true; > } > } > + > trigger_off(&auxtrace_snapshot_trigger); > trigger_off(&switch_output_trigger); > > + if (opts->auxtrace_snapshot_on_exit) > + record__auxtrace_snapshot_exit(rec); > + > if (forks && workload_exec_errno) { > char msg[STRERR_BUFSIZE]; > const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg)); > diff --git a/tools/perf/perf.h b/tools/perf/perf.h > index 74d0124d38f3..dc0a7a237887 100644 > --- a/tools/perf/perf.h > +++ b/tools/perf/perf.h > @@ -57,6 +57,7 @@ struct record_opts { > bool running_time; > bool full_auxtrace; > bool auxtrace_snapshot_mode; > + bool auxtrace_snapshot_on_exit; > bool record_namespaces; > bool record_switch_events; > bool all_kernel; > diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c > index 65728cdeefb6..72ce4c5e7c78 100644 > --- a/tools/perf/util/auxtrace.c > +++ b/tools/perf/util/auxtrace.c > @@ -539,9 +539,9 @@ int auxtrace_record__snapshot_start(struct auxtrace_record *itr) > return 0; > } > > -int auxtrace_record__snapshot_finish(struct auxtrace_record *itr) > +int auxtrace_record__snapshot_finish(struct auxtrace_record *itr, bool on_exit) > { > - if (itr && itr->snapshot_finish) > + if (!on_exit && itr && itr->snapshot_finish)
You are assuming you know what every ->snapshot_finish() does. It would be better to pass on_exit to ->snapshot_finish().
> return itr->snapshot_finish(itr); > return 0; > } > @@ -577,6 +577,16 @@ int auxtrace_parse_snapshot_options(struct auxtrace_record *itr, > if (!str) > return 0; > > + /* PMU-agnostic options */ > + switch (*str) { > + case 'e': > + opts->auxtrace_snapshot_on_exit = true; > + str++; > + break; > + default: > + break; > + } > + > if (itr) > return itr->parse_snapshot_options(itr, opts, str); > > diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h > index 17eb04a1da4d..8ccabacd0b11 100644 > --- a/tools/perf/util/auxtrace.h > +++ b/tools/perf/util/auxtrace.h > @@ -499,7 +499,7 @@ int auxtrace_record__info_fill(struct auxtrace_record *itr, > size_t priv_size); > void auxtrace_record__free(struct auxtrace_record *itr); > int auxtrace_record__snapshot_start(struct auxtrace_record *itr); > -int auxtrace_record__snapshot_finish(struct auxtrace_record *itr); > +int auxtrace_record__snapshot_finish(struct auxtrace_record *itr, bool on_exit); > int auxtrace_record__find_snapshot(struct auxtrace_record *itr, int idx, > struct auxtrace_mmap *mm, > unsigned char *data, u64 *head, u64 *old); >
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