From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 887B3C2BA2B for ; Fri, 17 Apr 2020 00:54:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E48D2064A for ; Fri, 17 Apr 2020 00:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728704AbgDQAyF (ORCPT ); Thu, 16 Apr 2020 20:54:05 -0400 Received: from mga05.intel.com ([192.55.52.43]:14430 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725858AbgDQAyF (ORCPT ); Thu, 16 Apr 2020 20:54:05 -0400 IronPort-SDR: v7U9cyEAuUd4tpBLlTETgaDYiwR1Aw4cFkEe2n5hckkLU5EojOiNia2f1XVRmP2deqNGwHqvDr 6dX7ISAGk7Fg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2020 17:54:04 -0700 IronPort-SDR: 9nrEFpP1p+k6NEwvNMf+6A30nG/noeLSahwQAPg1nLbSbDHwJC3beW6IcXWRudUHHd/vym74vE Tmgz4TiuNuDA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,392,1580803200"; d="scan'208";a="278199854" Received: from kbl-ppc.sh.intel.com ([10.239.159.118]) by fmsmga004.fm.intel.com with ESMTP; 16 Apr 2020 17:54:02 -0700 From: Jin Yao To: acme@kernel.org, jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com Cc: Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com, Jin Yao Subject: [PATCH] perf stat: Improve runtime stat for interval mode Date: Fri, 17 Apr 2020 08:51:54 +0800 Message-Id: <20200417005154.9024-1-yao.jin@linux.intel.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For interval mode, the metric is printed after # if it exists. But it's not calculated by the counts generated in this interval. See following examples, root@kbl-ppc:~# perf stat -M CPI -I1000 --interval-count 2 # time counts unit events 1.000422803 764,809 inst_retired.any # 2.9 CPI 1.000422803 2,234,932 cycles 2.001464585 1,960,061 inst_retired.any # 1.6 CPI 2.001464585 4,022,591 cycles The second CPI should not be 1.6 (4,022,591/1,960,061 is 2.1) root@kbl-ppc:~# perf stat -e cycles,instructions -I1000 --interval-count 2 # time counts unit events 1.000429493 2,869,311 cycles 1.000429493 816,875 instructions # 0.28 insn per cycle 2.001516426 9,260,973 cycles 2.001516426 5,250,634 instructions # 0.87 insn per cycle The second 'insn per cycle' should not be 0.87 (5,250,634/9,260,973 is 0.57). The current code uses a global variable rt_stat for tracking and updating the std dev of runtime stat. Unlike the counts, rt_stat is not reset for interval. While the counts are reset for interval. perf_stat_process_counter() { if (config->interval) init_stats(ps->res_stats); } So for interval, the rt_stat should be reset either. This patch resets rt_stat before read_counters, so the runtime stat is only calculated by the counts generated in this interval. With this patch, root@kbl-ppc:~# perf stat -M CPI -I1000 --interval-count 2 # time counts unit events 1.000420924 2,408,818 inst_retired.any # 2.1 CPI 1.000420924 5,010,111 cycles 2.001448579 2,798,407 inst_retired.any # 1.6 CPI 2.001448579 4,599,861 cycles root@kbl-ppc:~# perf stat -e cycles,instructions -I1000 --interval-count 2 # time counts unit events 1.000428555 2,769,714 cycles 1.000428555 774,462 instructions # 0.28 insn per cycle 2.001471562 3,595,904 cycles 2.001471562 1,243,703 instructions # 0.35 insn per cycle Now the second 'insn per cycle' and CPI are calculated by the counts generated in this interval. Signed-off-by: Jin Yao --- tools/perf/Documentation/perf-stat.txt | 2 ++ tools/perf/builtin-stat.c | 1 + tools/perf/util/stat-shadow.c | 5 +++++ tools/perf/util/stat.h | 1 + 4 files changed, 9 insertions(+) diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index 4d56586b2fb9..3fb5028aef08 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -176,6 +176,8 @@ Print count deltas every N milliseconds (minimum: 1ms) The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution. example: 'perf stat -I 1000 -e cycles -a sleep 5' +If the metric exists, it is calculated by the counts generated in this interval and the metric is printed after #. + --interval-count times:: Print count deltas for fixed number of times. This option should be used together with "-I" option. diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index ec053dc1e35c..d5c326ff46d0 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -359,6 +359,7 @@ static void process_interval(void) clock_gettime(CLOCK_MONOTONIC, &ts); diff_timespec(&rs, &ts, &ref_time); + perf_stat__reset_rt_stat(); read_counters(&rs); if (STAT_RECORD) { diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c index 1ad5c5be7e97..c8f5ca6c8749 100644 --- a/tools/perf/util/stat-shadow.c +++ b/tools/perf/util/stat-shadow.c @@ -186,6 +186,11 @@ void perf_stat__reset_shadow_stats(void) memset(&walltime_nsecs_stats, 0, sizeof(walltime_nsecs_stats)); } +void perf_stat__reset_rt_stat(void) +{ + reset_stat(&rt_stat); +} + void perf_stat__reset_shadow_per_stat(struct runtime_stat *st) { reset_stat(st); diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h index b4fdfaa7f2c0..2975494166dd 100644 --- a/tools/perf/util/stat.h +++ b/tools/perf/util/stat.h @@ -176,6 +176,7 @@ void runtime_stat__init(struct runtime_stat *st); void runtime_stat__exit(struct runtime_stat *st); void perf_stat__init_shadow_stats(void); void perf_stat__reset_shadow_stats(void); +void perf_stat__reset_rt_stat(void); void perf_stat__reset_shadow_per_stat(struct runtime_stat *st); void perf_stat__update_shadow_stats(struct evsel *counter, u64 count, int cpu, struct runtime_stat *st); -- 2.17.1