summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/record.c
diff options
context:
space:
mode:
authorJiri Olsa <jolsa@redhat.com>2013-11-05 15:14:47 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-11-05 15:15:08 -0300
commit714647bdc516330e4405b39677d7f763e016c685 (patch)
tree13aaae6374601031ff2393d11ee8a28d37072a6d /tools/perf/util/record.c
parenta9862418547e818aa5842840aecfa81d733b97e9 (diff)
downloadlinux-714647bdc516330e4405b39677d7f763e016c685.tar.gz
linux-714647bdc516330e4405b39677d7f763e016c685.tar.bz2
linux-714647bdc516330e4405b39677d7f763e016c685.zip
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 <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1383660887-1734-4-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/record.c')
-rw-r--r--tools/perf/util/record.c71
1 files changed, 71 insertions, 0 deletions
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);
+}