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-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);
+}
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