From: Jaswinder Singh Rajput Date: Sat, 27 Jun 2009 18:19:09 +0000 (+0530) Subject: perf stat: Micro-optimize the code: memcpy is only required if no event is selected... X-Git-Tag: v2.6.31-rc2~30^2~8 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=c3043569dc8fbe9228b76174f15d1a7152c48a20 perf stat: Micro-optimize the code: memcpy is only required if no event is selected and !null_run Set attrs and nr_counters if no event is selected and !null_run. Setting of attrs should depend on number of counters, so we need to memcpy only for sizeof(default_attrs) Also set nr_counters as ARRAY_SIZE(default_attrs) in place of hardcoded value. Signed-off-by: Jaswinder Singh Rajput Cc: Peter Zijlstra LKML-Reference: <1246126749.32198.16.camel@hpdv5.satnam> Signed-off-by: Ingo Molnar --- diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 3840a70..3e5ea4e 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -46,7 +46,7 @@ #include #include -static struct perf_counter_attr default_attrs[MAX_COUNTERS] = { +static struct perf_counter_attr default_attrs[] = { { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK }, { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES}, @@ -477,16 +477,17 @@ int cmd_stat(int argc, const char **argv, const char *prefix) { int status; - memcpy(attrs, default_attrs, sizeof(attrs)); - argc = parse_options(argc, argv, options, stat_usage, 0); if (!argc) usage_with_options(stat_usage, options); if (run_count <= 0 || run_count > MAX_RUN) usage_with_options(stat_usage, options); - if (!null_run && !nr_counters) - nr_counters = 8; + /* Set attrs and nr_counters if no event is selected and !null_run */ + if (!null_run && !nr_counters) { + memcpy(attrs, default_attrs, sizeof(default_attrs)); + nr_counters = ARRAY_SIZE(default_attrs); + } nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); assert(nr_cpus <= MAX_NR_CPUS);