Re: [PATCH v6 3/7] perf record: Split output into multiple files via '--switch-output'

["Wangnan (F)" <wangnan0@huawei.com>]

On 2016/4/28 5:32, Arnaldo Carvalho de Melo wrote:
> Em Wed, Apr 20, 2016 at 06:59:50PM +0000, Wang Nan escreveu:
>> Allow 'perf record' to split its output into multiple files.
>>
>> For example:
> I squashed:
>
> ->  360   T 04/20 Wang Nan        (1.7K) ├─>[PATCH v6 6/7]
> perf record: Re-synthesize tracking events after output switching
>
> Into this patch, so that we don't have the problem in the bisection
> history where samples don't get resolved to the existing threads not
> synthesized in the perf.data.N where N > the first timestamp.
>
> Please holler if you disagree, I doubt you will tho :-)

Sorry for the late. I'm okay for your work.

Thank you.

> - Arnaldo
>
>   
>>    # ~/perf record -a --timestamp-filename --switch-output &
>>    [1] 10763
>>    # kill -s SIGUSR2 10763
>>    [ perf record: dump data: Woken up 1 times ]
>>    # [ perf record: Dump perf.data.2015122622314468 ]
>>
>>    # kill -s SIGUSR2 10763
>>    [ perf record: dump data: Woken up 1 times ]
>>    # [ perf record: Dump perf.data.2015122622314762 ]
>>
>>    # kill -s SIGUSR2 10763
>>    [ perf record: dump data: Woken up 1 times ]
>>    #[ perf record: Dump perf.data.2015122622315171 ]
>>
>>    # fg
>>    perf record -a --timestamp-filename --switch-output
>>    ^C[ perf record: Woken up 1 times to write data ]
>>    [ perf record: Dump perf.data.2015122622315513 ]
>>    [ perf record: Captured and wrote 0.014 MB perf.data.<timestamp> (296 samples) ]
>>
>>    # ls -l
>>    total 920
>>    -rw------- 1 root root 797692 Dec 26 22:31 perf.data.2015122622314468
>>    -rw------- 1 root root  59960 Dec 26 22:31 perf.data.2015122622314762
>>    -rw------- 1 root root  59912 Dec 26 22:31 perf.data.2015122622315171
>>    -rw------- 1 root root  19220 Dec 26 22:31 perf.data.2015122622315513
>>
>> Signed-off-by: Wang Nan <wangnan0@huawei.com>
>> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>> Cc: Adrian Hunter <adrian.hunter@intel.com>
>> Cc: Jiri Olsa <jolsa@kernel.org>
>> Cc: Masami Hiramatsu <mhiramat@kernel.org>
>> Cc: Namhyung Kim <namhyung@kernel.org>
>> Cc: Zefan Li <lizefan@huawei.com>
>> Cc: pi3orama@163.com
>> Link: http://lkml.kernel.org/r/1460643725-167413-3-git-send-email-wangnan0@huawei.com
>> Signed-off-by: He Kuang <hekuang@huawei.com>
>> [ Added man page entry ]
>> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>> ---
>>   tools/perf/Documentation/perf-record.txt |  8 ++++++++
>>   tools/perf/builtin-record.c              | 33 ++++++++++++++++++++++++++++++--
>>   2 files changed, 39 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
>> index 19aa175..a77a431 100644
>> --- a/tools/perf/Documentation/perf-record.txt
>> +++ b/tools/perf/Documentation/perf-record.txt
>> @@ -347,6 +347,14 @@ Configure all used events to run in kernel space.
>>   --all-user::
>>   Configure all used events to run in user space.
>>   
>> +--switch-output::
>> +Generate multiple perf.data files, timestamp prefixed, switching to a new one
>> +when receiving a SIGUSR2.
>> +
>> +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
>> +particular perf.data snapshot should be kept or not.
>> +
>>   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 f4710c8..72246e2 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -58,6 +58,7 @@ struct record {
>>   	bool			no_buildid_cache_set;
>>   	bool			buildid_all;
>>   	bool			timestamp_filename;
>> +	bool			switch_output;
>>   	unsigned long long	samples;
>>   };
>>   
>> @@ -130,6 +131,7 @@ 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)
>>   {
>> @@ -650,9 +652,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>   	signal(SIGINT, sig_handler);
>>   	signal(SIGTERM, sig_handler);
>>   
>> -	if (rec->opts.auxtrace_snapshot_mode) {
>> +	if (rec->opts.auxtrace_snapshot_mode || rec->switch_output) {
>>   		signal(SIGUSR2, snapshot_sig_handler);
>> -		trigger_on(&auxtrace_snapshot_trigger);
>> +		if (rec->opts.auxtrace_snapshot_mode)
>> +			trigger_on(&auxtrace_snapshot_trigger);
>> +		if (rec->switch_output)
>> +			trigger_on(&switch_output_trigger);
>>   	} else {
>>   		signal(SIGUSR2, SIG_IGN);
>>   	}
>> @@ -782,11 +787,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>   	}
>>   
>>   	trigger_ready(&auxtrace_snapshot_trigger);
>> +	trigger_ready(&switch_output_trigger);
>>   	for (;;) {
>>   		unsigned long long hits = rec->samples;
>>   
>>   		if (record__mmap_read_all(rec) < 0) {
>>   			trigger_error(&auxtrace_snapshot_trigger);
>> +			trigger_error(&switch_output_trigger);
>>   			err = -1;
>>   			goto out_child;
>>   		}
>> @@ -802,6 +809,22 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>   			}
>>   		}
>>   
>> +		if (trigger_is_hit(&switch_output_trigger)) {
>> +			trigger_ready(&switch_output_trigger);
>> +
>> +			if (!quiet)
>> +				fprintf(stderr, "[ perf record: dump data: Woken up %ld times ]\n",
>> +					waking);
>> +			waking = 0;
>> +			fd = record__switch_output(rec, false);
>> +			if (fd < 0) {
>> +				pr_err("Failed to switch to new file\n");
>> +				trigger_error(&switch_output_trigger);
>> +				err = fd;
>> +				goto out_child;
>> +			}
>> +		}
>> +
>>   		if (hits == rec->samples) {
>>   			if (done || draining)
>>   				break;
>> @@ -830,6 +853,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>   		}
>>   	}
>>   	trigger_off(&auxtrace_snapshot_trigger);
>> +	trigger_off(&switch_output_trigger);
>>   
>>   	if (forks && workload_exec_errno) {
>>   		char msg[STRERR_BUFSIZE];
>> @@ -1263,6 +1287,8 @@ struct option __record_options[] = {
>>   		    "Record build-id of all DSOs regardless of hits"),
>>   	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
>>   		    "append timestamp to output filename"),
>> +	OPT_BOOLEAN(0, "switch-output", &record.switch_output,
>> +		    "Switch output when receive SIGUSR2"),
>>   	OPT_END()
>>   };
>>   
>> @@ -1417,4 +1443,7 @@ static void snapshot_sig_handler(int sig __maybe_unused)
>>   		if (auxtrace_record__snapshot_start(record.itr))
>>   			trigger_error(&auxtrace_snapshot_trigger);
>>   	}
>> +
>> +	if (trigger_is_ready(&switch_output_trigger))
>> +		trigger_hit(&switch_output_trigger);
>>   }
>> -- 
>> 1.8.3.4