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

From: Jiwei Sun
Date: Thu Feb 21 2019 - 21:38:16 EST


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@xxxxxxxxxxxxx>
>> ---
>> 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
>>
>