Messages in this thread Patch in this message | | | Subject | Re: [PATCH v3 20/50] perf record: Be lazier in allocating lost samples buffer | From | Yang Jihong <> | Date | Wed, 25 Oct 2023 11:44:19 +0800 |
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Hello,
On 2023/10/25 6:23, Ian Rogers 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); > - 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); > + } > }
Can zalloc for `lost` be moved to __record__save_lost_samples? This simplifies the code.
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index dcf288a4fb9a..8d2eb746031a 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1888,14 +1888,25 @@ record__switch_output(struct record *rec, bool at_exit) }
static void __record__save_lost_samples(struct record *rec, struct evsel *evsel, - struct perf_record_lost_samples *lost, + struct perf_record_lost_samples **plost, int cpu_idx, int thread_idx, u64 lost_count, u16 misc_flag) { struct perf_sample_id *sid; struct perf_sample sample = {}; + struct perf_record_lost_samples *lost = *plost; int id_hdr_size;
+ if (!lost) { + lost = zalloc(PERF_SAMPLE_MAX_SIZE); + if (!lost) { + pr_debug("Memory allocation failed\n"); + return; + } + lost->header.type = PERF_RECORD_LOST_SAMPLES; + *plost = lost; + } + lost->lost = lost_count; if (evsel->core.ids) { sid = xyarray__entry(evsel->core.sample_id, cpu_idx, thread_idx); @@ -1912,21 +1923,13 @@ 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); - 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; @@ -1949,7 +1952,7 @@ static void record__read_lost_samples(struct record *rec) }
if (count.lost) { - __record__save_lost_samples(rec, evsel, lost, + __record__save_lost_samples(rec, evsel, &lost, x, y, count.lost, 0); } } @@ -1957,11 +1960,12 @@ static void record__read_lost_samples(struct record *rec)
lost_count = perf_bpf_filter__lost_count(evsel); if (lost_count) - __record__save_lost_samples(rec, evsel, lost, 0, 0, lost_count, + __record__save_lost_samples(rec, evsel, &lost, 0, 0, lost_count, PERF_RECORD_MISC_LOST_SAMPLES_BPF); } out: - free(lost); + if (lost) + free(lost); }
static volatile sig_atomic_t workload_exec_errno;
Thanks, Yang
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