From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932359Ab0EDOAg (ORCPT ); Tue, 4 May 2010 10:00:36 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:59012 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932186Ab0EDOA3 (ORCPT ); Tue, 4 May 2010 10:00:29 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Anton Blanchard , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Frederic Weisbecker , Eric B Munson , Arnaldo Carvalho de Melo Subject: [PATCH 3/3] perf: Fix performance issue with perf report Date: Tue, 4 May 2010 11:00:07 -0300 Message-Id: <1272981607-28723-4-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.6.2.5 In-Reply-To: <1272981607-28723-1-git-send-email-acme@infradead.org> References: <1272981607-28723-1-git-send-email-acme@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.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: Anton Blanchard On a large machine we spend a lot of time in perf_header__find_attr when running perf report. If we are parsing a file without PERF_SAMPLE_ID then for each sample we call perf_header__find_attr and loop through all counter IDs, never finding a match. As the machine gets larger there are more per cpu counters and we spend an awful lot of time in there. The patch below initialises each sample id to -1ULL and checks for this in perf_header__find_attr. We may need to do something more intelligent eventually (eg a hash lookup from counter id to attr) but this at least fixes the most common usage of perf report. Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Eric B Munson Acked-by: Eric B Munson LKML-Reference: <20100504111915.GB14636@kryten> Signed-off-by: Anton Blanchard -- Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.c | 1 + tools/perf/util/header.c | 8 ++++++++ 2 files changed, 9 insertions(+), 0 deletions(-) diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 1757b0f..2477270 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -713,6 +713,7 @@ int event__parse_sample(event_t *event, u64 type, struct sample_data *data) array++; } + data->id = -1ULL; if (type & PERF_SAMPLE_ID) { data->id = *array; array++; diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 2b9f898..8847bec 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -922,6 +922,14 @@ perf_header__find_attr(u64 id, struct perf_header *header) { int i; + /* + * We set id to -1 if the data file doesn't contain sample + * ids. Check for this and avoid walking through the entire + * list of ids which may be large. + */ + if (id == -1ULL) + return NULL; + for (i = 0; i < header->attrs; i++) { struct perf_header_attr *attr = header->attr[i]; int j; -- 1.6.2.5