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-rw-r--r--tools/perf/Documentation/perf-stat.txt5
-rw-r--r--tools/perf/builtin-stat.c13
2 files changed, 12 insertions, 6 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 47469abdcc1c..4e074a660826 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -128,8 +128,9 @@ perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- m
-I msecs::
--interval-print msecs::
- Print count deltas every N milliseconds (minimum: 100ms)
- example: perf stat -I 1000 -e cycles -a sleep 5
+Print count deltas every N milliseconds (minimum: 10ms)
+The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
+ example: 'perf stat -I 1000 -e cycles -a sleep 5'
--per-socket::
Aggregate counts per processor socket for system-wide mode measurements. This
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a96fb5c3bedb..5ef88f760b12 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1179,7 +1179,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
OPT_STRING(0, "post", &post_cmd, "command",
"command to run after to the measured command"),
OPT_UINTEGER('I', "interval-print", &stat_config.interval,
- "print counts at regular interval in ms (>= 100)"),
+ "print counts at regular interval in ms (>= 10)"),
OPT_SET_UINT(0, "per-socket", &stat_config.aggr_mode,
"aggregate counts per processor socket", AGGR_SOCKET),
OPT_SET_UINT(0, "per-core", &stat_config.aggr_mode,
@@ -1332,9 +1332,14 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
thread_map__read_comms(evsel_list->threads);
if (interval && interval < 100) {
- pr_err("print interval must be >= 100ms\n");
- parse_options_usage(stat_usage, options, "I", 1);
- goto out;
+ if (interval < 10) {
+ pr_err("print interval must be >= 10ms\n");
+ parse_options_usage(stat_usage, options, "I", 1);
+ goto out;
+ } else
+ pr_warning("print interval < 100ms. "
+ "The overhead percentage could be high in some cases. "
+ "Please proceed with caution.\n");
}
if (perf_evlist__alloc_stats(evsel_list, interval))