diff options
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 7 | ||||
| -rw-r--r-- | tools/perf/builtin-record.c | 2 | ||||
| -rw-r--r-- | tools/perf/perf.h | 1 | ||||
| -rw-r--r-- | tools/perf/util/record.c | 20 |
4 files changed, 24 insertions, 6 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 94f2faebc7f0..cc37b3a4be76 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -191,11 +191,16 @@ OPTIONS -i:: --no-inherit:: Child tasks do not inherit counters. + -F:: --freq=:: Profile at this frequency. Use 'max' to use the currently maximum allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate - sysctl. + sysctl. Will throttle down to the currently maximum allowed frequency. + See --strict-freq. + +--strict-freq:: + Fail if the specified frequency can't be used. -m:: --mmap-pages=:: diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index e1821eea14ef..62387942a1d5 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1543,6 +1543,8 @@ static struct option __record_options[] = { OPT_BOOLEAN(0, "tail-synthesize", &record.opts.tail_synthesize, "synthesize non-sample events at the end of output"), OPT_BOOLEAN(0, "overwrite", &record.opts.overwrite, "use overwrite mode"), + OPT_BOOLEAN(0, "strict-freq", &record.opts.strict_freq, + "Fail if the specified frequency can't be used"), OPT_CALLBACK('F', "freq", &record.opts, "freq or 'max'", "profile at this frequency", record__parse_freq), diff --git a/tools/perf/perf.h b/tools/perf/perf.h index a5df8bf73a68..007e0dfd5ce3 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -61,6 +61,7 @@ struct record_opts { bool tail_synthesize; bool overwrite; bool ignore_missing_thread; + bool strict_freq; unsigned int freq; unsigned int mmap_pages; unsigned int auxtrace_mmap_pages; diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index acabf54ceccb..4f1a82e76d39 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -216,11 +216,21 @@ static int record_opts__config_freq(struct record_opts *opts) * User specified frequency is over current maximum. */ if (user_freq && (max_rate < opts->freq)) { - pr_err("Maximum frequency rate (%u) reached.\n" - "Please use -F freq option with lower value or consider\n" - "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n", - max_rate); - return -1; + if (opts->strict_freq) { + pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n" + " Please use -F freq option with a lower value or consider\n" + " tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n", + max_rate); + return -1; + } else { + pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n" + " The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n" + " The kernel will lower it when perf's interrupts take too long.\n" + " Use --strict-freq to disable this throttling, refusing to record.\n", + max_rate, opts->freq, max_rate); + + opts->freq = max_rate; + } } /* |