Messages in this thread | | | From | Namhyung Kim <> | Date | Wed, 25 Oct 2023 12:00:56 -0700 | Subject | Re: [PATCH v3 20/50] perf record: Be lazier in allocating lost samples buffer |
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On Tue, Oct 24, 2023 at 3:25 PM Ian Rogers <irogers@google.com> wrote: > > Wait until a lost sample occurs to allocate the lost samples buffer, > often the buffer isn't necessary. This saves a 64kb allocation and > 5.3kb of peak memory consumption. > > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/builtin-record.c | 29 +++++++++++++++++++---------- > 1 file changed, 19 insertions(+), 10 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 9b4f3805ca92..b6c8c1371b39 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1924,21 +1924,13 @@ static void __record__save_lost_samples(struct record *rec, struct evsel *evsel, > static void record__read_lost_samples(struct record *rec) > { > struct perf_session *session = rec->session; > - struct perf_record_lost_samples *lost; > + struct perf_record_lost_samples *lost = NULL; > struct evsel *evsel; > > /* there was an error during record__open */ > if (session->evlist == NULL) > return; > > - lost = zalloc(PERF_SAMPLE_MAX_SIZE);
Sorry for naively choosing the max size. :-p It could be sizeof(*lost) + machine->id_hdr_size.
Thanks, Namhyung
> - if (lost == NULL) { > - pr_debug("Memory allocation failed\n"); > - return; > - } > - > - lost->header.type = PERF_RECORD_LOST_SAMPLES; > - > evlist__for_each_entry(session->evlist, evsel) { > struct xyarray *xy = evsel->core.sample_id; > u64 lost_count; > @@ -1961,6 +1953,14 @@ static void record__read_lost_samples(struct record *rec) > } > > if (count.lost) { > + if (!lost) { > + lost = zalloc(PERF_SAMPLE_MAX_SIZE); > + if (!lost) { > + pr_debug("Memory allocation failed\n"); > + return; > + } > + lost->header.type = PERF_RECORD_LOST_SAMPLES; > + } > __record__save_lost_samples(rec, evsel, lost, > x, y, count.lost, 0); > } > @@ -1968,9 +1968,18 @@ static void record__read_lost_samples(struct record *rec) > } > > lost_count = perf_bpf_filter__lost_count(evsel); > - if (lost_count) > + if (lost_count) { > + if (!lost) { > + lost = zalloc(PERF_SAMPLE_MAX_SIZE); > + if (!lost) { > + pr_debug("Memory allocation failed\n"); > + return; > + } > + lost->header.type = PERF_RECORD_LOST_SAMPLES; > + } > __record__save_lost_samples(rec, evsel, lost, 0, 0, lost_count, > PERF_RECORD_MISC_LOST_SAMPLES_BPF); > + } > } > out: > free(lost); > -- > 2.42.0.758.gaed0368e0e-goog >
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