Commit ce7b0e42 authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Arnaldo Carvalho de Melo
Browse files

perf record: Add an option to take an AUX snapshot on exit 



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 ]

Co-developed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190806144101.62892-1-alexander.shishkin@linux.intel.com


[ Fixed up !HAVE_AUXTRACE_SUPPORT build in builtin-record.c, adding 2 missing __maybe_unused ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 73e5de70

tools/perf/Documentation/perf-record.txt

+8 −3
Original line number Diff line number Diff line
@@ -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,

tools/perf/builtin-record.c

+31 −4
Original line number Diff line number Diff line
@@ -613,19 +613,35 @@ out: 
	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);

	if (trigger_is_error(&auxtrace_snapshot_trigger))

		return -1;



	return 0;

}



static int record__auxtrace_init(struct record *rec)

{

	int err;
@@ -654,7 +670,8 @@ 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 __maybe_unused)

{

}
@@ -664,6 +681,12 @@ int auxtrace_record__snapshot_start(struct auxtrace_record *itr __maybe_unused) 
	return 0;

}



static inline

int record__auxtrace_snapshot_exit(struct record *rec __maybe_unused)

{

	return 0;

}



static int record__auxtrace_init(struct record *rec __maybe_unused)

{

	return 0;
@@ -1536,7 +1559,7 @@ 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 +1632,13 @@ 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));

tools/perf/perf.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

tools/perf/util/auxtrace.c

+12 −2
Original line number Diff line number Diff line
@@ -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)

		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);

tools/perf/util/auxtrace.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE