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 06EEDECAAA1 for ; Thu, 15 Sep 2022 12:26:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230085AbiIOM0i (ORCPT ); Thu, 15 Sep 2022 08:26:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229912AbiIOM0b (ORCPT ); Thu, 15 Sep 2022 08:26:31 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DEA1785B5; Thu, 15 Sep 2022 05:26:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663244790; x=1694780790; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=haHRJRLUtGiMpejZ9zvS+1gtLxrDjI6bwRU3M7poV3I=; b=O1eBHE+DSptm2dkVcXLzIak1pmqG8BJDlKmntyD6cfEC3zwt6ulxsvaI rfZ7h0im/kAJ6QIoBgZ9VkudrXra9sb6w20O6XZd8y/G7uZGk52qMlSCH 6x46Kx3pYys7D4cJwmWOJwWa8vVy7D9NC722i/dlh9jbpzCTtTGblVPFD +Z55GwtCJ4be4fX/FtYd6tGemyX5aMgU3ycOrwOzj0URMsAAGUgPKctOf oe/518rBNF89XCcTMgtRkYz4faUJS/xP39kqUrFg9DPzMkPSCXBtMZQIG IGR2VLYirQOU0j51Kb6sBXhpZAO4eaz74oMMMvWwNblojTBNQ97isOLHU g==; X-IronPort-AV: E=McAfee;i="6500,9779,10470"; a="298693709" X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="298693709" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 05:26:30 -0700 X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="685705669" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO ahunter-VirtualBox.home\044ger.corp.intel.com) ([10.252.60.17]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 05:26:28 -0700 From: Adrian Hunter To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , Namhyung Kim , Ian Rogers , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH 2/2] libperf evlist: Fix polling of system-wide events Date: Thu, 15 Sep 2022 15:26:12 +0300 Message-Id: <20220915122612.81738-3-adrian.hunter@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220915122612.81738-1-adrian.hunter@intel.com> References: <20220915122612.81738-1-adrian.hunter@intel.com> MIME-Version: 1.0 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Originally, (refer commit f90d194a867a ("perf evlist: Do not poll events that use the system_wide flag") there wasn't much reason to poll system-wide events because: 1. The mmaps get "merged" via set-output anyway (the per-cpu case) 2. perf reads all mmaps when any event is woken 3. system-wide mmaps do not fill up as fast as the mmaps for user selected events But there was 1 reason not to poll which was that it prevented correct termination due to POLLHUP on all user selected events. That issue is now easily resolved by using fdarray_flag__nonfilterable. With the advent of commit ae4f8ae16a07 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps"), system-wide mmaps can be used also in the per-thread case where reason 1 does not apply. Fix the omission of system-wide events from polling by using the fdarray_flag__nonfilterable flag. Example: Before: $ perf record --no-bpf-event -vvv -e intel_pt// --per-thread uname 2>err.txt Linux $ grep 'sys_perf_event_open.*=\|pollfd' err.txt sys_perf_event_open: pid 155076 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 155076 cpu -1 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 14 sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 15 thread_data[0x55fb43c29e80]: pollfd[0] <- event_fd=5 thread_data[0x55fb43c29e80]: pollfd[1] <- event_fd=6 thread_data[0x55fb43c29e80]: pollfd[2] <- non_perf_event fd=4 After: $ perf record --no-bpf-event -vvv -e intel_pt// --per-thread uname 2>err.txt Linux $ grep 'sys_perf_event_open.*=\|pollfd' err.txt sys_perf_event_open: pid 156316 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 156316 cpu -1 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 14 sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 15 thread_data[0x55cc19e58e80]: pollfd[0] <- event_fd=5 thread_data[0x55cc19e58e80]: pollfd[1] <- event_fd=6 thread_data[0x55cc19e58e80]: pollfd[2] <- event_fd=7 thread_data[0x55cc19e58e80]: pollfd[3] <- event_fd=9 thread_data[0x55cc19e58e80]: pollfd[4] <- event_fd=10 thread_data[0x55cc19e58e80]: pollfd[5] <- event_fd=11 thread_data[0x55cc19e58e80]: pollfd[6] <- event_fd=12 thread_data[0x55cc19e58e80]: pollfd[7] <- event_fd=13 thread_data[0x55cc19e58e80]: pollfd[8] <- event_fd=14 thread_data[0x55cc19e58e80]: pollfd[9] <- event_fd=15 thread_data[0x55cc19e58e80]: pollfd[10] <- non_perf_event fd=4 Fixes: ae4f8ae16a07 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter --- tools/lib/perf/evlist.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c index 80cc810c5097..0e7347d1583d 100644 --- a/tools/lib/perf/evlist.c +++ b/tools/lib/perf/evlist.c @@ -441,6 +441,7 @@ mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops, perf_evlist__for_each_entry(evlist, evsel) { bool overwrite = evsel->attr.write_backward; + enum fdarray_flags flgs; struct perf_mmap *map; int *output, fd, cpu; @@ -506,8 +507,8 @@ mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops, revent = !overwrite ? POLLIN : 0; - if (!evsel->system_wide && - perf_evlist__add_pollfd(evlist, fd, map, revent, fdarray_flag__default) < 0) { + flgs = evsel->system_wide ? fdarray_flag__nonfilterable : fdarray_flag__default; + if (perf_evlist__add_pollfd(evlist, fd, map, revent, flgs) < 0) { perf_mmap__put(map); return -1; } -- 2.25.1