Re: [PATCH v4] perf record: Add support for limit perf output file size

[Jiwei Sun]

Hi Jirka,

On 2019e9410f21f% 21:41, Jiri Olsa wrote:
> On Wed, Sep 25, 2019 at 03:06:37PM +0800, Jiwei Sun wrote:
> 
> SNIP
> 
>>  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 48600c90cc7e..30904d2a3407 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -91,6 +91,7 @@ struct record {
>>      struct switch_output    switch_output;
>>      unsigned long long      samples;
>>      cpu_set_t               affinity_mask;
>> +    unsigned long           output_max_size;        /* = 0: unlimited */
>>  };
>>  
>>  static volatile int auxtrace_record__snapshot_started;
>> @@ -120,6 +121,12 @@ static bool switch_output_time(struct record *rec)
>>             trigger_is_ready(&switch_output_trigger);
>>  }
>>  
>> +static bool record__output_max_size_exceeded(struct record *rec)
>> +{
>> +    return rec->output_max_size &&
>> +           (rec->bytes_written >= rec->output_max_size);
>> +}
>> +
>>  static int record__write(struct record *rec, struct mmap *map 
>> __maybe_unused,
>>                       void *bf, size_t size)
>>  {
>> @@ -132,6 +139,12 @@ static int record__write(struct record *rec, struct 
>> mmap *map __maybe_unused,
>>  
>>      rec->bytes_written += size;
>>  
>> +    if (record__output_max_size_exceeded(rec)) {
>> +            WARN_ONCE(1, "WARNING: The perf data has already reached "
>> +                         "the limit, stop recording!\n");
> 
> I think the message whouldn't be a warning, the user asked for
> that, maybe something more like:
> 
>   [ perf record: perf size limit reached (XXMB), stopping session ]
> 
>> +            raise(SIGTERM);
> 
> could we just set 'done = 1' what's the benefit in killing perf?

Thanks for your suggestions. Yes, if just set "done == 1" is more efficient and 
more concise.
And I will modify it and the output format, and then send a v5 patch.
Thanks again.

Regards,
Jiwei

> 
> thanks,
> jirka
> 
>