From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755281Ab1A2WTk (ORCPT ); Sat, 29 Jan 2011 17:19:40 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:35649 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755185Ab1A2WTd (ORCPT ); Sat, 29 Jan 2011 17:19:33 -0500 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Frederic Weisbecker , Ingo Molnar , Mike Galbraith , Paul Mackerras , Peter Zijlstra , Stephane Eranian , Tom Zanussi Subject: [PATCH 3/7] perf evlist: Support non overwrite mode in perf_evlist__read_on_cpu Date: Sat, 29 Jan 2011 20:19:15 -0200 Message-Id: <1296339559-20914-4-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.6.2.5 In-Reply-To: <1296339559-20914-1-git-send-email-acme@infradead.org> References: <1296339559-20914-1-git-send-email-acme@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by canuck.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo I.e. stash the overwrite mode in struct perf_evlist and act accordingly in perf_evlist__read_on_cpu, not checking for overwrites and touching the tail after consuming one event, like perf record does, for instance. Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Tom Zanussi LKML-Reference: Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 35 ++++++++++++++++++++--------------- tools/perf/util/evlist.h | 1 + tools/perf/util/evsel.c | 1 + 3 files changed, 22 insertions(+), 15 deletions(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index df0610e..b498eec 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -116,24 +116,25 @@ event_t *perf_evlist__read_on_cpu(struct perf_evlist *evlist, int cpu) unsigned int old = md->prev; unsigned char *data = md->base + page_size; event_t *event = NULL; - int diff; - - /* - * If we're further behind than half the buffer, there's a chance - * the writer will bite our tail and mess up the samples under us. - * - * If we somehow ended up ahead of the head, we got messed up. - * - * In either case, truncate and restart at head. - */ - diff = head - old; - if (diff > md->mask / 2 || diff < 0) { - fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); + if (evlist->overwrite) { /* - * head points to a known good entry, start there. + * If we're further behind than half the buffer, there's a chance + * the writer will bite our tail and mess up the samples under us. + * + * If we somehow ended up ahead of the head, we got messed up. + * + * In either case, truncate and restart at head. */ - old = head; + int diff = head - old; + if (diff > md->mask / 2 || diff < 0) { + fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); + + /* + * head points to a known good entry, start there. + */ + old = head; + } } if (old != head) { @@ -166,5 +167,9 @@ event_t *perf_evlist__read_on_cpu(struct perf_evlist *evlist, int cpu) } md->prev = old; + + if (!evlist->overwrite) + perf_mmap__write_tail(md, old); + return event; } diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index acbe48e..2706ae4 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -16,6 +16,7 @@ struct perf_evlist { int nr_entries; int nr_fds; int mmap_len; + bool overwrite; event_t event_copy; struct perf_mmap *mmap; struct pollfd *pollfd; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 76ab553..f98b3e5 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -327,6 +327,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, struct cpu_map *cpus, perf_evlist__alloc_pollfd(evlist, cpus->nr, threads->nr) < 0) return -ENOMEM; + evlist->overwrite = overwrite; evlist->mmap_len = (pages + 1) * page_size; first_evsel = list_entry(evlist->entries.next, struct perf_evsel, node); -- 1.6.2.5