linux-kernel - Re: [PATCH] perf record: Add support for limit perf output file size

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Date:   Fri, 22 Feb 2019 10:34:38 +0800
From:   Jiwei Sun <Jiwei.Sun@...driver.com>
To:     Jiri Olsa <jolsa@...hat.com>
CC:     <peterz@...radead.org>, <mingo@...hat.com>, <acme@...nel.org>,
        <alexander.shishkin@...ux.intel.com>, <namhyung@...nel.org>,
        <ast@...nel.org>, <daniel@...earbox.net>, <kafai@...com>,
        <songliubraving@...com>, <yhs@...com>,
        <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH] perf record: Add support for limit perf output file size

Hi Jirka,

On 02/21/2019 05:56 PM, Jiri Olsa wrote:
> On Thu, Feb 21, 2019 at 02:44:19PM +0800, Jiwei Sun wrote:
>> The patch adds a new option to limit the output file size, then based
>> on it, we can create a wrapper of the perf command that uses the option
>> to avoid exhausting the disk space by the unconscious user.
>>
>> Signed-off-by: Jiwei Sun <jiwei.sun@...driver.com>
>> ---
>>  tools/perf/builtin-record.c | 39 +++++++++++++++++++++++++++++++++++++
>>  1 file changed, 39 insertions(+)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 882285fb9f64..28a03929166d 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -81,6 +81,7 @@ struct record {
>>  	bool			timestamp_boundary;
>>  	struct switch_output	switch_output;
>>  	unsigned long long	samples;
>> +	unsigned long		output_max_size;	/* = 0: unlimited */
> 
> please rebase to latest Arnaldo's perf/core,
> there are new fields in here now

OK, thanks for your response, and I will send a v2 patch based on the branch perf/core.

> 
>>  };
>>  
>>  static volatile int auxtrace_record__snapshot_started;
>> @@ -106,6 +107,12 @@ 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 perf_mmap *map __maybe_unused,
>>  			 void *bf, size_t size)
>>  {
>> @@ -118,6 +125,9 @@ static int record__write(struct record *rec, struct perf_mmap *map __maybe_unuse
>>  
>>  	rec->bytes_written += size;
>>  
>> +	if (record__output_max_size_exceeded(rec))
>> +		raise(SIGTERM);
> 
> perhaps display some message saying we reached the limit
> 
> other than that looks good to me

OK, I will add some warning message in the v2 patch.

Thanks,
Regards,
Jiwei

> 
> thanks,
> jirka
> 
> 
>> +
>>  	if (switch_output_size(rec))
>>  		trigger_hit(&switch_output_trigger);
>>  
>> @@ -1639,6 +1649,33 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
>>  	return -1;
>>  }
>>  
>> +static int parse_output_max_size(const struct option *opt, const char *str,
>> +				 int unset)
>> +{
>> +	unsigned long *s = (unsigned long *)opt->value;
>> +	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 },
>> +	};
>> +	unsigned long val;
>> +
>> +	if (unset) {
>> +		*s = 0;
>> +		return 0;
>> +	}
>> +
>> +	val = parse_tag_value(str, tags_size);
>> +	if (val != (unsigned long) -1) {
>> +		*s = val;
>> +		return 0;
>> +	}
>> +
>> +	return -1;
>> +}
>> +
>>  static int record__parse_mmap_pages(const struct option *opt,
>>  				    const char *str,
>>  				    int unset __maybe_unused)
>> @@ -1946,6 +1983,8 @@ static struct option __record_options[] = {
>>  		     &nr_cblocks_default, "n", "Use <n> control blocks in asynchronous trace writing mode (default: 1, max: 4)",
>>  		     record__aio_parse),
>>  #endif
>> +	OPT_CALLBACK(0, "output-max-size", &record.output_max_size,
>> +		     "size", "Output file maximum size", parse_output_max_size),
>>  	OPT_END()
>>  };
>>  
>> -- 
>> 2.20.1
>>
>