From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73CE012C46B; Fri, 10 May 2024 13:54:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715349250; cv=none; b=n6RQyPlFuTNgnO5R2dDZbP4EfOCfxm64EhRm9o4Uzuhd6/eczKCYRQP17ayRd/lJOgNKi+PsFlPO/r2f4qoAJrEiNEj4oJQk1yVHcw98EdE+wNxaDSG5KEblXXEE3kI/we/9o6bJIhHQUc06lCbyNegoQXpEKugjQrsrWGE8igU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715349250; c=relaxed/simple; bh=JykUQXVZnA9s05U9WJm3I8AGGS491GmkM8kocE4qnpo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VkWIVJggcY5ymRYZanZGPn+L6aheoDPqTPS7J/MQuVZYrXVszQMUUxszTNiPGnPTjb4pdGes/bliF9W4iZCTO2UyC1mNvjFaFjhGiEXBti7rb8SF/waB7ABoejzNPCxy5cUtO+S3aRXSfLgCa+sxMWVyL9XW0CfV0zisKgolMM8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TfhZINet; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TfhZINet" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10557C2BBFC; Fri, 10 May 2024 13:54:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715349250; bh=JykUQXVZnA9s05U9WJm3I8AGGS491GmkM8kocE4qnpo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TfhZINetWAppiYJSpUU15y4ofywLmWA44autqYr1VIuwdzpv6JdWGvkHR1v5Y5vVa KtSU9ohVTJWtu4sKjk8wxgv6QJzgZICVXw1o08Ft39frocdEavTw1OaJCPiazvjYkQ zPoXXMvZkfjF50z9Z1c3ozMBKe4wl80zB/rNOhnRp8vyokr7HtaxZfQBHuO7Rb3oOM HMTEbTJFmVFDuTd9j++6RZQkw/39aPQBnYMxWXqhfaR8VomSOUQkOi6j6tOFVyj8uV fSQN0GqnIoYYpOQpTTZc8QkpVwdRyPCE781v4wSUWCL4w5onowxstu2qht+WHdTy+m zv3r23SrWeNXg== Date: Fri, 10 May 2024 10:54:06 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ian Rogers , Kan Liang , Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org Subject: Re: [PATCH] perf tools: Ignore deleted cgroups Message-ID: References: <20240509182235.2319599-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240509182235.2319599-1-namhyung@kernel.org> On Thu, May 09, 2024 at 11:22:35AM -0700, Namhyung Kim wrote: > On a large system, cgroups can be created and deleted often. That means > there's a race between perf tools and cgroups when it gets the cgroup > name and opens the cgroup. I got a report that perf stat with many > cgroups failed a quite often due to the missing cgroups on such a large > machine. > > I think we can ignore such cgroups when expanding events and use id 0 if > it fails to read the cgroup id. IIUC 0 is not a vaild cgroup id so it > won't update event counts for the failed cgroups. Thanks, applied to perf-tools-next, - Arnaldo > Signed-off-by: Namhyung Kim > --- > tools/perf/util/bpf_counter_cgroup.c | 5 ++--- > tools/perf/util/cgroup.c | 4 +++- > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c > index 1c82377ed78b..ea29c372f339 100644 > --- a/tools/perf/util/bpf_counter_cgroup.c > +++ b/tools/perf/util/bpf_counter_cgroup.c > @@ -136,9 +136,8 @@ static int bperf_load_program(struct evlist *evlist) > cgrp = evsel->cgrp; > > if (read_cgroup_id(cgrp) < 0) { > - pr_err("Failed to get cgroup id\n"); > - err = -1; > - goto out; > + pr_debug("Failed to get cgroup id for %s\n", cgrp->name); > + cgrp->id = 0; > } > > map_fd = bpf_map__fd(skel->maps.cgrp_idx); > diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c > index fcb509058499..0f759dd96db7 100644 > --- a/tools/perf/util/cgroup.c > +++ b/tools/perf/util/cgroup.c > @@ -465,9 +465,11 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str, > name = cn->name + prefix_len; > if (name[0] == '/' && name[1]) > name++; > + > + /* the cgroup can go away in the meantime */ > cgrp = cgroup__new(name, open_cgroup); > if (cgrp == NULL) > - goto out_err; > + continue; > > leader = NULL; > evlist__for_each_entry(orig_list, pos) { > -- > 2.45.0.118.g7fe29c98d7-goog