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perf top: Drop samples which are behind the refresh rate

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Drop samples from processing thread if they get behind the latest event
read from the kernel maps. If it gets behind more than the refresh rate
(-d option), drop the sample.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/n/tip-x533ra5c1pgofvbtsizzuydd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2018-11-11 19:52:06 +01:00 committed by Arnaldo Carvalho de Melo
parent c94cef4beb
commit d63b9f6fea
1 changed files with 22 additions and 3 deletions
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25
tools/perf/builtin-top.c
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@ -833,6 +833,8 @@ perf_top__process_lost_samples(struct perf_top *top,
hists->stats.total_lost_samples += event->lost_samples.lost;
}
static u64 last_timestamp;
static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
{
struct record_opts *opts = &top->record_opts;
@ -845,14 +847,13 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
return;
while ((event = perf_mmap__read_event(md)) != NULL) {
u64 timestamp = -1ULL;
int ret;
ret = perf_evlist__parse_sample_timestamp(evlist, event, &timestamp);
ret = perf_evlist__parse_sample_timestamp(evlist, event, &last_timestamp);
if (ret && ret != -1)
break;
ret = ordered_events__queue(top->qe.in, event, timestamp, 0);
ret = ordered_events__queue(top->qe.in, event, last_timestamp, 0);
if (ret)
break;
@ -1084,6 +1085,21 @@ static void *process_thread(void *arg)
return NULL;
}
/*
* Allow only 'top->delay_secs' seconds behind samples.
*/
static int should_drop(struct ordered_event *qevent, struct perf_top *top)
{
union perf_event *event = qevent->event;
u64 delay_timestamp;
if (event->header.type != PERF_RECORD_SAMPLE)
return false;
delay_timestamp = qevent->timestamp + top->delay_secs * NSEC_PER_SEC;
return delay_timestamp < last_timestamp;
}
static int deliver_event(struct ordered_events *qe,
struct ordered_event *qevent)
{
@ -1096,6 +1112,9 @@ static int deliver_event(struct ordered_events *qe,
struct machine *machine;
int ret = -1;
if (should_drop(qevent, top))
return 0;
ret = perf_evlist__parse_sample(evlist, event, &sample);
if (ret) {
pr_err("Can't parse sample, err = %d\n", ret);