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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F256AC433F5 for ; Fri, 6 May 2022 09:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1390486AbiEFJbK (ORCPT ); Fri, 6 May 2022 05:31:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1390520AbiEFJbG (ORCPT ); Fri, 6 May 2022 05:31:06 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6DE564BC4 for ; Fri, 6 May 2022 02:27:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651829243; x=1683365243; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=J7XOmTu7TYPbzhxPJ7h4k1YCkR5C8gg9HSeJvj2JEgA=; b=AT+S2S6ZAx1qyr+QQMSVi29LeRWQ3joRHQjHyuJVhx1sQkCsYthtSr2p T81rlPAuSrjkoOm2Od1nLQObL5kP/cyaHjQAOdSHKnBJ5ZuEli67/v9/r NRepPzKksrDIKZu8iaWgqpM0eHDVbI4qAIzuQPcnuEHqSfBNm6Oa4tXQY VTDze2GA/KN8DbZYJMf5zlussiWoKcCGVUxeev2+S5ZzvjGNkQNqP6TLI 0j8LTXg+rUf4P3Do7iMauLts+Laz5vEhZ0fug9OoO+BDkU/oI3olTIOGI tOiGWJ+LkphIfLdEqJ8UqcgUo0nvuF5VcJlWqWNAgwTDhgPTXCp/X++z8 Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10338"; a="328956169" X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="328956169" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2022 02:27:23 -0700 X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="585883719" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.252.62.152]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2022 02:27:20 -0700 Message-ID: <077c06ad-e1f9-a86c-208e-5dc0d0f33bce@intel.com> Date: Fri, 6 May 2022 12:27:17 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.8.1 Subject: Re: [PATCH V1 13/23] perf evlist: Add evlist__add_system_wide_dummy() Content-Language: en-US To: Ian Rogers Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Alexey Bayduraev , Namhyung Kim , Leo Yan , linux-kernel@vger.kernel.org References: <20220505165639.361733-1-adrian.hunter@intel.com> <20220505165639.361733-14-adrian.hunter@intel.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/05/22 11:34, Ian Rogers wrote: > On Fri, May 6, 2022 at 1:14 AM Adrian Hunter wrote: >> >> On 6/05/22 02:56, Ian Rogers wrote: >>> On Thu, May 5, 2022 at 9:57 AM Adrian Hunter wrote: >>>> >>>> Add evlist__add_system_wide_dummy() to enable creating a system-wide dummy >>>> event that sets up the system-wide maps before map propagation. >>> >>> Perhaps this should be: >>> evlist__add_dummy_on_all_online_cpus() >> >> Ok, but offline isn't an option, so I'll drop 'online' from the name. > > I'm not sure I follow. There can be CPUs that are offline (echo 0 > > /sys/devices/system/cpu/cpu2/online) and then brought online while > perf is running. The output obviously won't be right as we're missing > dummy events. Losing online from the name here seems to remove a > useful clue. perf_event_open() will not accept events on offline CPUs. > > Thanks, > Ian > >>> my thoughts being that a system wide dummy sounds like the dummy CPU >>> map, ie {-1} whilst what happens here is opening on all online CPUs >>> {0-35} on a 36 hyperthread system. Note also that the libperf >>> cpu_map__read_all_cpu_map code doesn't discover sysfs' mount properly, >>> as done in: >>> tools/lib/api/fs/fs.h >>> Some tech debt. >>> >>>> For convenience, add evlist__add_aux_dummy() so that the logic can be used >>>> whether or not the event needs to be system-wide. >>>> >>>> Signed-off-by: Adrian Hunter >>>> --- >>>> tools/perf/util/evlist.c | 40 ++++++++++++++++++++++++++++++++++++++++ >>>> tools/perf/util/evlist.h | 5 +++++ >>>> 2 files changed, 45 insertions(+) >>>> >>>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c >>>> index 78c47cbafbc2..58ea562ddbd2 100644 >>>> --- a/tools/perf/util/evlist.c >>>> +++ b/tools/perf/util/evlist.c >>>> @@ -264,6 +264,46 @@ int evlist__add_dummy(struct evlist *evlist) >>>> return 0; >>>> } >>>> >>>> +static void evlist__add_system_wide(struct evlist *evlist, struct evsel *evsel) >>> >>> This would be: >>> evlist__add_on_all_online_cpus(..) >>> >>>> +{ >>>> + evsel->core.system_wide = true; >>>> + >>>> + /* All CPUs */ >>>> + perf_cpu_map__put(evsel->core.own_cpus); >>>> + evsel->core.own_cpus = perf_cpu_map__new(NULL); >>>> + perf_cpu_map__put(evsel->core.cpus); >>>> + evsel->core.cpus = perf_cpu_map__get(evsel->core.own_cpus); >>>> + >>>> + /* No threads */ >>>> + perf_thread_map__put(evsel->core.threads); >>>> + evsel->core.threads = perf_thread_map__new_dummy(); >>>> + >>>> + evlist__add(evlist, evsel); >>>> +} >>>> + >>>> +struct evsel *evlist__add_aux_dummy(struct evlist *evlist, bool system_wide) >>>> +{ >>>> + struct evsel *evsel = evlist__dummy_event(evlist); >>>> + >>>> + if (!evsel) >>>> + return NULL; >>>> + >>>> + evsel->core.attr.exclude_kernel = 1; >>>> + evsel->core.attr.exclude_guest = 1; >>>> + evsel->core.attr.exclude_hv = 1; >>>> + evsel->core.attr.freq = 0; >>>> + evsel->core.attr.sample_period = 1; >>>> + evsel->no_aux_samples = true; >>>> + evsel->name = strdup("dummy:u"); >>>> + >>>> + if (system_wide) >>>> + evlist__add_system_wide(evlist, evsel); >>>> + else >>>> + evlist__add(evlist, evsel); >>>> + >>>> + return evsel; >>>> +} >>>> + >>>> static int evlist__add_attrs(struct evlist *evlist, struct perf_event_attr *attrs, size_t nr_attrs) >>>> { >>>> struct evsel *evsel, *n; >>>> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h >>>> index 4062f5aebfc1..dd1af114e033 100644 >>>> --- a/tools/perf/util/evlist.h >>>> +++ b/tools/perf/util/evlist.h >>>> @@ -114,6 +114,11 @@ int arch_evlist__add_default_attrs(struct evlist *evlist); >>>> struct evsel *arch_evlist__leader(struct list_head *list); >>>> >>>> int evlist__add_dummy(struct evlist *evlist); >>>> +struct evsel *evlist__add_aux_dummy(struct evlist *evlist, bool system_wide); >>>> +static inline struct evsel *evlist__add_system_wide_dummy(struct evlist *evlist) >>>> +{ >>>> + return evlist__add_aux_dummy(evlist, true); >>>> +} >>>> >>>> int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr, >>>> evsel__sb_cb_t cb, void *data); >>>> -- >>>> 2.25.1 >>>> >>