Re: [PATCH 6/7] perf record: Add switch-output size option argument

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Jan 03, 2017 at 09:19:59AM +0100, Jiri Olsa escreveu:
> It's now possible to specify the threshold size for
> perf.data like:
> 
>   $ perf record --switch-output=2G ...
> 
> Once it's reached, the current data are dumped in to the
> perf.data.<timestamp> file and session does on.

  s/does/goes/g

But:

[root@jouet ~]# perf record -F9000 -a --switch-output=1K sleep 5
[ perf record: dump data: Woken up 0 times ]
[ perf record: Dump perf.data.2017010311185502 ]
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017010311190003 ]
[ perf record: Woken up 0 times to write data ]
[ perf record: Dump perf.data.2017010311190020 ]
[ perf record: Captured and wrote 2.240 MB perf.data.<timestamp> ]
[root@jouet ~]# ls -larth perf.data.*
-rw-------. 1 root root 2.3M Jan  3 11:18 perf.data.2017010311181984
-rw-------. 1 root root 2.3M Jan  3 11:18 perf.data.2017010311182002
-rw-------. 1 root root 2.3M Jan  3 11:18 perf.data.2017010311185502
-rw-------. 1 root root 2.3M Jan  3 11:19 perf.data.2017010311190003
-rw-------. 1 root root 2.3M Jan  3 11:19 perf.data.2017010311190020
[root@jouet ~]#

What is that I am missing?

- Arnaldo
 
>   $ perf record --switch-output=2G ...
>   [ perf record: dump data: Woken up 7244 times ]
>   [ perf record: Dump perf.data.2017010214093746 ]
>   ...
> 
> The size is expected to be a number with appended unit
> character - B/K/M/G.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Wang Nan <wangnan0@huawei.com>
> Link: http://lkml.kernel.org/n/tip-xw4x8qj6aojox378q9ley29e@git.kernel.org
> ---
>  tools/perf/Documentation/perf-record.txt |  7 +++-
>  tools/perf/builtin-record.c              | 66 ++++++++++++++++++++++++++------
>  2 files changed, 59 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index 5054d9147f0f..d838354df417 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -421,9 +421,12 @@ Configure all used events to run in user space.
>  --timestamp-filename
>  Append timestamp to output file name.
>  
> ---switch-output::
> +--switch-output[=mode]::
>  Generate multiple perf.data files, timestamp prefixed, switching to a new one
> -when receiving a SIGUSR2.
> +based on 'mode' value:
> +  "signal" - when receiving a SIGUSR2 (default value) or
> +  <size>   - when reaching the size threshold, size is expected to
> +             be a number with appended unit character - B/K/M/G
>  
>  A possible use case is to, given an external event, slice the perf.data file
>  that gets then processed, possibly via a perf script, to decide if that
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index b503e5ebc1e7..42321a0fa80e 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -47,7 +47,9 @@
>  #include <linux/time64.h>
>  
>  struct switch_output {
> +	bool		 enabled;
>  	bool		 signal;
> +	unsigned long	 size;
>  	const char	*str;
>  	bool		 set;
>  };
> @@ -72,6 +74,23 @@ struct record {
>  	unsigned long long	samples;
>  };
>  
> +static volatile int auxtrace_record__snapshot_started;
> +static DEFINE_TRIGGER(auxtrace_snapshot_trigger);
> +static DEFINE_TRIGGER(switch_output_trigger);
> +
> +static bool switch_output_signal(struct record *rec)
> +{
> +	return rec->switch_output.signal &&
> +	       trigger_is_ready(&switch_output_trigger);
> +}
> +
> +static bool switch_output_size(struct record *rec)
> +{
> +	return rec->switch_output.size &&
> +	       trigger_is_ready(&switch_output_trigger) &&
> +	       (rec->bytes_written >= rec->switch_output.size);
> +}
> +
>  static int record__write(struct record *rec, void *bf, size_t size)
>  {
>  	if (perf_data_file__write(rec->session->file, bf, size) < 0) {
> @@ -80,6 +99,10 @@ static int record__write(struct record *rec, void *bf, size_t size)
>  	}
>  
>  	rec->bytes_written += size;
> +
> +	if (switch_output_size(rec))
> +		trigger_hit(&switch_output_trigger);
> +
>  	return 0;
>  }
>  
> @@ -199,10 +222,6 @@ static volatile int done;
>  static volatile int signr = -1;
>  static volatile int child_finished;
>  
> -static volatile int auxtrace_record__snapshot_started;
> -static DEFINE_TRIGGER(auxtrace_snapshot_trigger);
> -static DEFINE_TRIGGER(switch_output_trigger);
> -
>  static void sig_handler(int sig)
>  {
>  	if (sig == SIGCHLD)
> @@ -848,11 +867,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  	signal(SIGTERM, sig_handler);
>  	signal(SIGSEGV, sigsegv_handler);
>  
> -	if (rec->opts.auxtrace_snapshot_mode || rec->switch_output.signal) {
> +	if (rec->opts.auxtrace_snapshot_mode || rec->switch_output.enabled) {
>  		signal(SIGUSR2, snapshot_sig_handler);
>  		if (rec->opts.auxtrace_snapshot_mode)
>  			trigger_on(&auxtrace_snapshot_trigger);
> -		if (rec->switch_output.signal)
> +		if (rec->switch_output.enabled)
>  			trigger_on(&switch_output_trigger);
>  	} else {
>  		signal(SIGUSR2, SIG_IGN);
> @@ -1360,13 +1379,33 @@ static int record__parse_mmap_pages(const struct option *opt,
>  
>  static int switch_output_setup(struct switch_output *s)
>  {
> +	unsigned long val;
> +	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 },
> +	};
> +
>  	if (!strcmp(s->str, "signal")) {
>  		s->signal = true;
>  		pr_debug("switch-output with SIGUSR2 signal\n");
> -		return 0;
> +		goto enabled;
> +	}
> +
> +	val = parse_tag_value(s->str, tags_size);
> +	if (val != (unsigned long) -1) {
> +		s->size = val;
> +		pr_debug("switch-output with %s size threshold\n", s->str);
> +		goto enabled;
>  	}
>  
>  	return -1;
> +
> +enabled:
> +	s->enabled = true;
> +	return 0;
>  }
>  
>  static const char * const __record_usage[] = {
> @@ -1537,8 +1576,9 @@ static struct option __record_options[] = {
>  	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
>  		    "append timestamp to output filename"),
>  	OPT_STRING_OPTARG_SET(0, "switch-output", &record.switch_output.str,
> -			  &record.switch_output.set, "signal",
> -			  "Switch output when receive SIGUSR2", "signal"),
> +			  &record.switch_output.set, "signal,size",
> +			  "Switch output when receive SIGUSR2 or cross size threshold",
> +			  "signal"),
>  	OPT_BOOLEAN(0, "dry-run", &dry_run,
>  		    "Parse options then exit"),
>  	OPT_END()
> @@ -1602,7 +1642,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
>  		return -EINVAL;
>  	}
>  
> -	if (rec->switch_output.signal)
> +	if (rec->switch_output.enabled)
>  		rec->timestamp_filename = true;
>  
>  	if (!rec->itr) {
> @@ -1653,7 +1693,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
>  
>  	if (rec->no_buildid_cache || rec->no_buildid) {
>  		disable_buildid_cache();
> -	} else if (rec->switch_output.signal) {
> +	} else if (rec->switch_output.enabled) {
>  		/*
>  		 * In 'perf record --switch-output', disable buildid
>  		 * generation by default to reduce data file switching
> @@ -1745,6 +1785,8 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
>  
>  static void snapshot_sig_handler(int sig __maybe_unused)
>  {
> +	struct record *rec = &record;
> +
>  	if (trigger_is_ready(&auxtrace_snapshot_trigger)) {
>  		trigger_hit(&auxtrace_snapshot_trigger);
>  		auxtrace_record__snapshot_started = 1;
> @@ -1752,6 +1794,6 @@ static void snapshot_sig_handler(int sig __maybe_unused)
>  			trigger_error(&auxtrace_snapshot_trigger);
>  	}
>  
> -	if (trigger_is_ready(&switch_output_trigger))
> +	if (switch_output_signal(rec))
>  		trigger_hit(&switch_output_trigger);
>  }
> -- 
> 2.7.4