From d63b9f6fea7613e2fdc8a5ef7e17ecc9cf24bf9d Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Sun, 11 Nov 2018 19:52:06 +0100 Subject: perf top: Drop samples which are behind the refresh rate 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 Acked-by: David S. Miller Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Peter Zijlstra Link: https://lkml.kernel.org/n/tip-x533ra5c1pgofvbtsizzuydd@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-top.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) (limited to 'tools/perf/builtin-top.c') diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 50ec01eb7f57..234232d538c2 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -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, ×tamp); + 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); -- cgit v1.2.3