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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9EDFFC433E0 for ; Thu, 28 May 2020 01:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76D46208B8 for ; Thu, 28 May 2020 01:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726838AbgE1Brz (ORCPT ); Wed, 27 May 2020 21:47:55 -0400 Received: from mga18.intel.com ([134.134.136.126]:62093 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725959AbgE1Brz (ORCPT ); Wed, 27 May 2020 21:47:55 -0400 IronPort-SDR: L24yTQKrww9fAaFQW7cmryUiuYkLgt2+GbeUOtzNeXl8WLv9ZKtHwX9k2jStbL0dTjK9rerhCC 77aPrPmyZQ2g== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2020 18:47:52 -0700 IronPort-SDR: b0b5QU3LB8ar+xcFU3rRLap57wrS2qQRqXLqu2EQ1g41g1Ws+OykaEpZSYl4qBZhSwRLuub/V3 jktUuHeMRA+w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,443,1583222400"; d="scan'208";a="376212752" Received: from yjin15-mobl1.ccr.corp.intel.com (HELO [10.238.5.239]) ([10.238.5.239]) by fmsmga001.fm.intel.com with ESMTP; 27 May 2020 18:47:50 -0700 Subject: Re: [PATCH v2 1/2] perf evlist: Ensure grouped events with same cpu map To: Jiri Olsa Cc: acme@kernel.org, jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com References: <20200525065559.6422-1-yao.jin@linux.intel.com> <20200526115155.GE333164@krava> <32c4663a-6934-2a2d-79e2-7a335e3629a2@linux.intel.com> <20200527102805.GA420698@krava> <19b749fa-fa96-85ac-8c7d-10336ff7475a@linux.intel.com> <20200527162800.GC420698@krava> From: "Jin, Yao" Message-ID: <06a84164-98e9-f301-756a-a25c09297ae0@linux.intel.com> Date: Thu, 28 May 2020 09:47:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <20200527162800.GC420698@krava> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jiri, On 5/28/2020 12:28 AM, Jiri Olsa wrote: > On Wed, May 27, 2020 at 09:49:11PM +0800, Jin, Yao wrote: >> Hi Jiri, >> >> On 5/27/2020 6:28 PM, Jiri Olsa wrote: >>> On Wed, May 27, 2020 at 02:31:03PM +0800, Jin, Yao wrote: >>> >>> SNIP >>> >>>>> Thanks >>>>> Jin Yao >>>> >>>> Issue is found! >>>> >>>> It looks we can't set "pos->leader = pos" in either for_each_group_member() >>>> or in for_each_group_evsel() because it may exit the iteration immediately. >>>> >>>> evlist__for_each_entry(evlist, evsel) { >>>> if (evsel->leader == evsel) >>>> continue; >>>> >>>> if (cpu_maps_matched(evsel->leader, evsel)) >>>> continue; >>>> >>>> pr_warning("WARNING: event cpu maps are not fully matched, " >>>> "disable group\n"); >>>> >>>> for_each_group_member(pos, evsel->leader) { >>>> pos->leader = pos; >>>> pos->core.nr_members = 0; >>>> } >>>> >>>> Let me use the example of '{cycles,unc_cbo_cache_lookup.any_i}' again. >>>> >>>> In evlist: >>>> cycles, >>>> unc_cbo_cache_lookup.any_i, >>>> unc_cbo_cache_lookup.any_i, >>>> unc_cbo_cache_lookup.any_i, >>>> unc_cbo_cache_lookup.any_i, >>>> >>>> When we reach the for_each_group_member at first time, evsel is the first >>>> unc_cbo_cache_lookup.any_i and evsel->leader is cycles. pos is same as the >>>> evsel (the first unc_cbo_cache_lookup.any_i). >>>> >>>> Once we execute "pos->leader = pos;", it's actually "evsel->leader = evsel". >>>> So now evsel->leader is changed to the first unc_cbo_cache_lookup.any_i. >>>> >>>> In next iteration, pos is the second unc_cbo_cache_lookup.any_i. pos->leader >>>> is cycles but unfortunately evsel->leader has been changed to the first >>>> unc_cbo_cache_lookup.any_i. So iteration stops immediately. >>> >>> hum, AFAICS the iteration will not break but continue to next evsel and >>> pass the 'continue' for another group member.. what do I miss? >>> >>> jirka >>> >> >> Let me use this example again. >> >> cycles, >> unc_cbo_cache_lookup.any_i, >> unc_cbo_cache_lookup.any_i, >> unc_cbo_cache_lookup.any_i, >> unc_cbo_cache_lookup.any_i, >> >> Yes, once for_each_group_member breaks (due to the issue in 'pos->leader = >> pos'), evlist__for_each_entry will continue to the second >> unc_cbo_cache_lookup.any_i. But now evsel->leader != evsel (evsel->leader is >> "cycles"), so it will go to cpu_maps_matched. >> >> But actually we don't need to go to cpu_maps_matched again. >> >> for_each_group_member(pos, evsel->leader) { >> pos->leader = pos; >> pos->core.nr_members = 0; >> } >> >> If we solve the issue in above code, for_each_group_member doesn't break, >> the leaders of all members in this group will be set to themselves. >> >> if (evsel->leader == evsel) >> continue; > > I see.. the problem is in the for_each_group_member, how about > saving the leader into separate variable, like below > > jirka > > > --- > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index f789103d8306..a754cad3f5a0 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -189,6 +189,51 @@ static struct perf_stat_config stat_config = { > .big_num = true, > }; > > +static bool cpus_map_matched(struct evsel *a, struct evsel *b) > +{ > + if (!a->core.cpus && !b->core.cpus) > + return true; > + > + if (!a->core.cpus || !b->core.cpus) > + return false; > + > + if (a->core.cpus->nr != b->core.cpus->nr) > + return false; > + > + for (int i = 0; i < a->core.cpus->nr; i++) { > + if (a->core.cpus->map[i] != b->core.cpus->map[i]) > + return false; > + } > + > + return true; > +} > + > + > +static void evlist__check_cpu_maps(struct evlist *evlist) > +{ > + struct evsel *evsel, *pos, *leader; > + > + evlist__for_each_entry(evlist, evsel) { > + char buf[1024]; > + > + leader = evsel->leader; > + if (leader == evsel) > + continue; > + if (cpus_map_matched(leader, evsel)) > + continue; > + > + evsel__group_desc(leader, buf, sizeof(buf)); > + WARN_ONCE(1, "WARNING: event cpu maps do not match, disabling group:\n"); > + pr_warning(" %s\n", buf); > + > + for_each_group_evsel(pos, leader) { > + pos->leader = pos; > + pos->core.nr_members = 0; > + } > + evsel->leader->core.nr_members = 0; > + } > +} > + > static inline void diff_timespec(struct timespec *r, struct timespec *a, > struct timespec *b) > { > @@ -1956,6 +2001,8 @@ int cmd_stat(int argc, const char **argv) > } else if (argc && !strncmp(argv[0], "rep", 3)) > return __cmd_report(argc, argv); > > + evlist__check_cpu_maps(evsel_list); > + > interval = stat_config.interval; > timeout = stat_config.timeout; > > This patch looks good. I guess you will post this patch, right? Thanks so much! :) Thanks Jin Yao