Alexander Shishkin <alexander.shish...@linux.intel.com> writes:
> 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.shish...@linux.intel.com>
> ---
> tools/perf/Documentation/perf-record.txt | 11 ++++++++---
> tools/perf/builtin-record.c | 4 ++++
> tools/perf/perf.h | 1 +
> tools/perf/util/auxtrace.c | 10 ++++++++++
> 4 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-record.txt
> b/tools/perf/Documentation/perf-record.txt
> index ea3789d05e..164ffce680 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -387,9 +387,14 @@ 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 70340ff200..42d1b7aeee 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1136,6 +1136,10 @@ static int __cmd_record(struct record *rec, int argc,
> const char **argv)
> disabled = true;
> }
> }
> +
> + if (opts->auxtrace_snapshot_on_exit)
> + record__read_auxtrace_snapshot(rec);
> +
> trigger_off(&auxtrace_snapshot_trigger);
> trigger_off(&switch_output_trigger);
>
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index 806c216a10..b79c57485b 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -50,6 +50,7 @@ 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 0daf63b9ee..25ad4445b0 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -564,6 +564,16 @@ 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);
>
> --
> 2.11.0
