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

From: Jiri Olsa
Date: Thu Feb 21 2019 - 04:56:30 EST


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

> };
>
> 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

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
>