From: Thomas Gleixner Date: Tue, 30 Nov 2010 17:49:49 +0000 (+0000) Subject: perf session: Keep file mmaped instead of malloc/memcpy X-Git-Tag: MMI-PSA29.97-13-9~20972^2~93 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=fe17420784a6d3602e98f798731369fa05936cbe;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git perf session: Keep file mmaped instead of malloc/memcpy Profiling perf with perf revealed that a large part of the processing time is spent in malloc/memcpy/free in the sample ordering code. That code copies the data from the mmap into malloc'ed memory. That's silly. We can keep the mmap and just store the pointer in the queuing data structure. For 64 bit this is not a problem as we map the whole file anyway. On 32bit we keep 8 maps around and unmap the oldest before mmaping the next chunk of the file. Performance gain: 2.95s -> 1.23s (Faktor 2.4) Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Frederic Weisbecker LKML-Reference: <20101130163820.278787719@linutronix.de> Signed-off-by: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 752577fdb16e..c98958314102 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -418,7 +418,6 @@ static void flush_sample_queue(struct perf_session *s, os->last_flush = iter->timestamp; list_del(&iter->list); - free(iter->event); free(iter); } @@ -531,7 +530,6 @@ static int queue_sample_event(event_t *event, struct sample_data *data, u64 timestamp = data->time; struct sample_queue *new; - if (timestamp < s->ordered_samples.last_flush) { printf("Warning: Timestamp below last timeslice flush\n"); return -EINVAL; @@ -542,14 +540,7 @@ static int queue_sample_event(event_t *event, struct sample_data *data, return -ENOMEM; new->timestamp = timestamp; - - new->event = malloc(event->header.size); - if (!new->event) { - free(new); - return -ENOMEM; - } - - memcpy(new->event, event, event->header.size); + new->event = event; __queue_sample_event(new, s); @@ -747,12 +738,12 @@ int __perf_session__process_events(struct perf_session *session, u64 file_size, struct perf_event_ops *ops) { u64 head, page_offset, file_offset, file_pos, progress_next; - int err, mmap_prot, mmap_flags; + int err, mmap_prot, mmap_flags, map_idx = 0; struct ui_progress *progress; size_t page_size, mmap_size; + char *buf, *mmaps[8]; event_t *event; uint32_t size; - char *buf; perf_event_ops__fill_defaults(ops); @@ -774,6 +765,8 @@ int __perf_session__process_events(struct perf_session *session, if (mmap_size > file_size) mmap_size = file_size; + memset(mmaps, 0, sizeof(mmaps)); + mmap_prot = PROT_READ; mmap_flags = MAP_SHARED; @@ -789,6 +782,8 @@ remap: err = -errno; goto out_err; } + mmaps[map_idx] = buf; + map_idx = (map_idx + 1) & (ARRAY_SIZE(mmaps) - 1); file_pos = file_offset + head; more: @@ -801,10 +796,10 @@ more: size = 8; if (head + event->header.size >= mmap_size) { - int munmap_ret; - - munmap_ret = munmap(buf, mmap_size); - assert(munmap_ret == 0); + if (mmaps[map_idx]) { + munmap(mmaps[map_idx], mmap_size); + mmaps[map_idx] = NULL; + } page_offset = page_size * (head / page_size); file_offset += page_offset;