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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 BFF61C43441 for ; Thu, 15 Nov 2018 14:17:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8ACEA2145D for ; Thu, 15 Nov 2018 14:17:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8ACEA2145D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388256AbeKPAZw (ORCPT ); Thu, 15 Nov 2018 19:25:52 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47150 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729035AbeKPAZw (ORCPT ); Thu, 15 Nov 2018 19:25:52 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A2F2EC0669AB; Thu, 15 Nov 2018 14:17:50 +0000 (UTC) Received: from krava (unknown [10.40.205.128]) by smtp.corp.redhat.com (Postfix) with SMTP id 19419620D6; Thu, 15 Nov 2018 14:17:46 +0000 (UTC) Date: Thu, 15 Nov 2018 15:17:45 +0100 From: Jiri Olsa To: Ravi Bangoria Cc: acme@kernel.org, alexander.shishkin@linux.intel.com, namhyung@kernel.org, yao.jin@linux.intel.com, linux-kernel@vger.kernel.org, yuzhoujian@didichuxing.com, tmricht@linux.vnet.ibm.com, anton@samba.org Subject: Re: [RFC 2/2] perf stat: Fix shadow stats for clock events Message-ID: <20181115141745.GJ9600@krava> References: <20181115095533.16930-1-ravi.bangoria@linux.ibm.com> <20181115095533.16930-2-ravi.bangoria@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115095533.16930-2-ravi.bangoria@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 15 Nov 2018 14:17:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15, 2018 at 03:25:33PM +0530, Ravi Bangoria wrote: > Commit 0aa802a79469 ("perf stat: Get rid of extra clock display > function") introduced scale and unit for clock events. Thus, > perf_stat__update_shadow_stats() now saves scaled values of > clock events in msecs, instead of original nsecs. But while > calculating values of shadow stats we still consider clock > event values in nsecs. This results in a wrong shadow stat > values. Ex, > > # ./perf stat -e task-clock,cycles ls > > 2.62 msec task-clock:u # 0.624 CPUs utilized > 2,501,536 cycles:u # 1250768.000 GHz > > Fix this by considering clock events's saved stats in msecs: > > # ./perf stat -e task-clock,cycles ls > > 2.42 msec task-clock:u # 0.754 CPUs utilized > 2,338,747 cycles:u # 1.169 GHz > > Note: > The problem with this approach is, we are losing fractional part > while converting nsecs to msecs. This results in a sightly different > values of shadow stats. yea, could we just leave the NSEC instead? like below jirka --- diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c index f4bad808bdd9..da8857df238e 100644 --- a/tools/perf/util/stat-shadow.c +++ b/tools/perf/util/stat-shadow.c @@ -209,11 +209,12 @@ void perf_stat__update_shadow_stats(struct perf_evsel *counter, u64 count, int cpu, struct runtime_stat *st) { int ctx = evsel_context(counter); + u64 count_ns = count; count *= counter->scale; if (perf_evsel__is_clock(counter)) - update_runtime_stat(st, STAT_NSECS, 0, cpu, count); + update_runtime_stat(st, STAT_NSECS, 0, cpu, count_ns); else if (perf_evsel__match(counter, HARDWARE, HW_CPU_CYCLES)) update_runtime_stat(st, STAT_CYCLES, ctx, cpu, count); else if (perf_stat_evsel__is(counter, CYCLES_IN_TX))