From 714647bdc516330e4405b39677d7f763e016c685 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 5 Nov 2013 15:14:47 +0100 Subject: [PATCH] perf tools: Check maximum frequency rate for record/top Adding the check for maximum allowed frequency rate defined in following file: /proc/sys/kernel/perf_event_max_sample_rate When we cross the maximum value we fail and display detailed error message with advise. $ perf record -F 3000 ls Maximum frequency rate (2000) reached. Please use -F freq option with lower value or consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. In case user does not specify the frequency and the default value cross the maximum, we display warning and set the frequency value to the current maximum. $ perf record ls Lowering default frequency rate to 2000. Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. Same messages are used for 'perf top'. Signed-off-by: Jiri Olsa Cc: Adrian Hunter Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1383660887-1734-4-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 15 +------- tools/perf/builtin-top.c | 15 +------- tools/perf/util/evlist.h | 1 + tools/perf/util/record.c | 71 +++++++++++++++++++++++++++++++++++++ 4 files changed, 74 insertions(+), 28 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 8b45fcead5f6..ea4c04f7437e 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -958,20 +958,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) if (perf_evlist__create_maps(evsel_list, &rec->opts.target) < 0) usage_with_options(record_usage, record_options); - if (rec->opts.user_interval != ULLONG_MAX) - rec->opts.default_interval = rec->opts.user_interval; - if (rec->opts.user_freq != UINT_MAX) - rec->opts.freq = rec->opts.user_freq; - - /* - * User specified count overrides default frequency. - */ - if (rec->opts.default_interval) - rec->opts.freq = 0; - else if (rec->opts.freq) { - rec->opts.default_interval = rec->opts.freq; - } else { - ui__error("frequency and count are zero, aborting\n"); + if (perf_record_opts__config(&rec->opts)) { err = -EINVAL; goto out_free_fd; } diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 21897f0ffcd3..9acca8856ccb 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1209,20 +1209,7 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused) if (top.delay_secs < 1) top.delay_secs = 1; - if (opts->user_interval != ULLONG_MAX) - opts->default_interval = opts->user_interval; - if (opts->user_freq != UINT_MAX) - opts->freq = opts->user_freq; - - /* - * User specified count overrides default frequency. - */ - if (opts->default_interval) - opts->freq = 0; - else if (opts->freq) { - opts->default_interval = opts->freq; - } else { - ui__error("frequency and count are zero, aborting\n"); + if (perf_record_opts__config(opts)) { status = -EINVAL; goto out_delete_maps; } diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index 6e8acc9abe38..0617ce2a0679 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -99,6 +99,7 @@ void perf_evlist__set_id_pos(struct perf_evlist *evlist); bool perf_can_sample_identifier(void); void perf_evlist__config(struct perf_evlist *evlist, struct perf_record_opts *opts); +int perf_record_opts__config(struct perf_record_opts *opts); int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct perf_target *target, diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index 18d73aa2f0f8..c8845b107f60 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -2,6 +2,8 @@ #include "evsel.h" #include "cpumap.h" #include "parse-events.h" +#include "fs.h" +#include "util.h" typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel); @@ -106,3 +108,72 @@ void perf_evlist__config(struct perf_evlist *evlist, perf_evlist__set_id_pos(evlist); } + +static int get_max_rate(unsigned int *rate) +{ + char path[PATH_MAX]; + const char *procfs = procfs__mountpoint(); + + if (!procfs) + return -1; + + snprintf(path, PATH_MAX, + "%s/sys/kernel/perf_event_max_sample_rate", procfs); + + return filename__read_int(path, (int *) rate); +} + +static int perf_record_opts__config_freq(struct perf_record_opts *opts) +{ + bool user_freq = opts->user_freq != UINT_MAX; + unsigned int max_rate; + + if (opts->user_interval != ULLONG_MAX) + opts->default_interval = opts->user_interval; + if (user_freq) + opts->freq = opts->user_freq; + + /* + * User specified count overrides default frequency. + */ + if (opts->default_interval) + opts->freq = 0; + else if (opts->freq) { + opts->default_interval = opts->freq; + } else { + pr_err("frequency and count are zero, aborting\n"); + return -1; + } + + if (get_max_rate(&max_rate)) + return 0; + + /* + * 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; + } + + /* + * Default frequency is over current maximum. + */ + if (max_rate < opts->freq) { + pr_warning("Lowering default frequency rate to %u.\n" + "Please consider tweaking " + "/proc/sys/kernel/perf_event_max_sample_rate.\n", + max_rate); + opts->freq = max_rate; + } + + return 0; +} + +int perf_record_opts__config(struct perf_record_opts *opts) +{ + return perf_record_opts__config_freq(opts); +} -- 2.39.5