diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2010-04-14 22:09:02 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2010-04-15 04:12:52 +0200 |
| commit | f92128193094c288bc315db1694fafeaeb7ee1d0 (patch) | |
| tree | 492e6ead96b08c4a5d8761d75252afb9a084f66a /tools/perf/builtin-record.c | |
| parent | bdef3b02ceeb97f5f67fcfa6dff13c4e70b34fb7 (diff) | |
perf: Make the trace events sample period default to 1
Trace events are mostly used for tracing and then require not to
be lost when possible. As opposite to hardware events that really
require to trigger after a given sample period, trace events mostly
need to trigger everytime.
It is a frustrating experience to trace with perf and realize we
lost a lot of events because we forgot the "-c 1" option.
Then default sample_period to 1 for trace events but let the user
override it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'tools/perf/builtin-record.c')
| -rw-r--r-- | tools/perf/builtin-record.c | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index dcda8993082..ca2affc9233 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -33,11 +33,13 @@ enum write_mode_t { static int *fd[MAX_NR_CPUS][MAX_COUNTERS]; +static unsigned int user_interval = UINT_MAX; static long default_interval = 0; static int nr_cpus = 0; static unsigned int page_size; static unsigned int mmap_pages = 128; +static unsigned int user_freq = UINT_MAX; static int freq = 1000; static int output; static const char *output_name = "perf.data"; @@ -255,10 +257,19 @@ static void create_counter(int counter, int cpu) if (nr_counters > 1) attr->sample_type |= PERF_SAMPLE_ID; - if (freq) { - attr->sample_type |= PERF_SAMPLE_PERIOD; - attr->freq = 1; - attr->sample_freq = freq; + /* + * We default some events to a 1 default interval. But keep + * it a weak assumption overridable by the user. + */ + if (!attr->sample_period || (user_freq != UINT_MAX && + user_interval != UINT_MAX)) { + if (freq) { + attr->sample_type |= PERF_SAMPLE_PERIOD; + attr->freq = 1; + attr->sample_freq = freq; + } else { + attr->sample_period = default_interval; + } } if (no_samples) @@ -689,13 +700,13 @@ static const struct option options[] = { "CPU to profile on"), OPT_BOOLEAN('f', "force", &force, "overwrite existing data file (deprecated)"), - OPT_LONG('c', "count", &default_interval, + OPT_LONG('c', "count", &user_interval, "event period to sample"), OPT_STRING('o', "output", &output_name, "file", "output file name"), OPT_BOOLEAN('i', "inherit", &inherit, "child tasks inherit counters"), - OPT_INTEGER('F', "freq", &freq, + OPT_INTEGER('F', "freq", &user_freq, "profile at this frequency"), OPT_INTEGER('m', "mmap-pages", &mmap_pages, "number of mmap data pages"), @@ -716,7 +727,6 @@ static const struct option options[] = { int cmd_record(int argc, const char **argv, const char *prefix __used) { - int counter; int i,j; argc = parse_options(argc, argv, options, record_usage, @@ -774,6 +784,11 @@ int cmd_record(int argc, const char **argv, const char *prefix __used) if (!event_array) return -ENOMEM; + if (user_interval != UINT_MAX) + default_interval = user_interval; + if (user_freq != UINT_MAX) + freq = user_freq; + /* * User specified count overrides default frequency. */ @@ -786,12 +801,5 @@ int cmd_record(int argc, const char **argv, const char *prefix __used) exit(EXIT_FAILURE); } - for (counter = 0; counter < nr_counters; counter++) { - if (attrs[counter].sample_period) - continue; - - attrs[counter].sample_period = default_interval; - } - return __cmd_record(argc, argv); } |