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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1B0BEC433E0 for ; Thu, 18 Feb 2021 16:09:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE13B64EAD for ; Thu, 18 Feb 2021 16:09:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233105AbhBRQH4 (ORCPT ); Thu, 18 Feb 2021 11:07:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:57012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230218AbhBRNbu (ORCPT ); Thu, 18 Feb 2021 08:31:50 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3C81F64E6F; Thu, 18 Feb 2021 13:20:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613654458; bh=Kuqf2NInYXNr+gfhAndoPFe/SnE6eqArm4wmmi3RI2s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=COoc+IbYJGzdkwv/6guRpEoek8w7TlM/69ZNG1DrfzgMozaI2wdGnYVliCnJECNYo RuyB35Ukjx6nC0wzsMXwbSRDCK35PuBRRhr/CVvNAS2Ak/sStwJsl96QgHovJEoy3f wkB3l6SpCKdcPLJOeBY8ZDOXdcxw9cv4lOOqymPV1KP9099qE74ECF43Nat6/Zd29s pV8sJ/LzV53e6JmLipqPPdkkGPjn1oaIhwF1j7vS4V7VFPAA9a+55oyWeeGTPBeEXC 7P1NNwP+/HqR+KDkEZ72zpwW7E92vHFSKkr5oMLoKWnAGQY/Rptth+EESOaspO+9ts O4H3ezuMg3AWw== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id BFC9240CD9; Thu, 18 Feb 2021 10:20:53 -0300 (-03) Date: Thu, 18 Feb 2021 10:20:53 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Namhyung Kim , Yang Jihong , amistry@google.com, Alexey Budankov , Adrian Hunter , Alexander Shishkin , Mark Rutland , Ingo Molnar , Peter Zijlstra , linux-kernel , zhangjinhao2@huawei.com Subject: Re: [PATCH] perf record: Fix continue profiling after draining the buffer Message-ID: References: <20210205065001.23252-1-yangjihong1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, Feb 05, 2021 at 11:46:12AM +0100, Jiri Olsa escreveu: > On Fri, Feb 05, 2021 at 07:35:22PM +0900, Namhyung Kim wrote: > > Hello, > > > > On Fri, Feb 5, 2021 at 3:50 PM Yang Jihong wrote: > > > > > > commit da231338ec9c098707c8a1e4d8a50e2400e2fe17 uses eventfd to solve rare race > > > where the setting and checking of 'done' which add done_fd to pollfd. > > > When draining buffer, revents of done_fd is 0 and evlist__filter_pollfd > > > function returns a non-zero value. > > > As a result, perf record does not stop profiling. > > > > > > The following simple scenarios can trigger this condition: > > > > > > sleep 10 & > > > perf record -p $! > > > > > > After the sleep process exits, perf record should stop profiling and exit. > > > However, perf record keeps running. > > > > > > If pollfd revents contains only POLLERR or POLLHUP, > > > perf record indicates that buffer is draining and need to stop profiling. > > > Use fdarray_flag__nonfilterable to set done eventfd to nonfilterable objects, > > > so that evlist__filter_pollfd does not filter and check done eventfd. > > > > > > Fixes: da231338ec9c (perf record: Use an eventfd to wakeup when done) > > > Signed-off-by: Yang Jihong > > > --- > > > tools/perf/builtin-record.c | 2 +- > > > tools/perf/util/evlist.c | 8 ++++++++ > > > tools/perf/util/evlist.h | 4 ++++ > > > 3 files changed, 13 insertions(+), 1 deletion(-) > > > > > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > > > index fd3911650612..51e593e896ea 100644 > > > --- a/tools/perf/builtin-record.c > > > +++ b/tools/perf/builtin-record.c > > > @@ -1663,7 +1663,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) > > > status = -1; > > > goto out_delete_session; > > > } > > > - err = evlist__add_pollfd(rec->evlist, done_fd); > > > + err = evlist__add_wakeup_eventfd(rec->evlist, done_fd); > > > if (err < 0) { > > > pr_err("Failed to add wakeup eventfd to poll list\n"); > > > status = err; > > > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > > > index 05363a7247c4..fea4c1e8010d 100644 > > > --- a/tools/perf/util/evlist.c > > > +++ b/tools/perf/util/evlist.c > > > @@ -572,6 +572,14 @@ int evlist__filter_pollfd(struct evlist *evlist, short revents_and_mask) > > > return perf_evlist__filter_pollfd(&evlist->core, revents_and_mask); > > > } > > > > > > +#ifdef HAVE_EVENTFD_SUPPORT > > > +int evlist__add_wakeup_eventfd(struct evlist *evlist, int fd) > > > +{ > > > + return perf_evlist__add_pollfd(&evlist->core, fd, NULL, POLLIN, > > > + fdarray_flag__nonfilterable); > > > +} > > > +#endif > > > > Does it build when HAVE_EVENTFD_SUPPORT is not defined? > > yea, I was wondering the same.. but it's called only from > code within HAVE_EVENTFD_SUPPORT ifdef Yes, this can't work on systems without eventfd, it will simply not build, and why do we have to make the definition of this function conditional on HAVE_EVENTFD_SUPPORT? I'm missing something :-\ Yeah, this whole call to evlist__add_pollfd is already surrounded by #ifdef HAVE_EVENTFD_SUPPORT: 1656 if (zstd_init(&session->zstd_data, rec->opts.comp_level) < 0) { 1657 pr_err("Compression initialization failed.\n"); 1658 return -1; 1659 } 1660 #ifdef HAVE_EVENTFD_SUPPORT 1661 done_fd = eventfd(0, EFD_NONBLOCK); 1662 if (done_fd < 0) { 1663 pr_err("Failed to create wakeup eventfd, error: %m\n"); 1664 status = -1; 1665 goto out_delete_session; 1666 } 1667 err = evlist__add_pollfd(rec->evlist, done_fd); 1668 if (err < 0) { 1669 pr_err("Failed to add wakeup eventfd to poll list\n"); 1670 status = err; 1671 goto out_delete_session; 1672 } 1673 #endif // HAVE_EVENTFD_SUPPORT 1674 1675 session->header.env.comp_type = PERF_COMP_ZSTD; 1676 session->header.env.comp_level = rec->opts.comp_level; Jiri, does your Acked-by stands? Namhyung? - Arnaldo > jirka > > > > > Thanks, > > Namhyung > > > > > > > + > > > int evlist__poll(struct evlist *evlist, int timeout) > > > { > > > return perf_evlist__poll(&evlist->core, timeout); > > > diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h > > > index 1aae75895dea..6d4d62151bc8 100644 > > > --- a/tools/perf/util/evlist.h > > > +++ b/tools/perf/util/evlist.h > > > @@ -142,6 +142,10 @@ struct evsel *evlist__find_tracepoint_by_name(struct evlist *evlist, const char > > > int evlist__add_pollfd(struct evlist *evlist, int fd); > > > int evlist__filter_pollfd(struct evlist *evlist, short revents_and_mask); > > > > > > +#ifdef HAVE_EVENTFD_SUPPORT > > > +int evlist__add_wakeup_eventfd(struct evlist *evlist, int fd); > > > +#endif > > > + > > > int evlist__poll(struct evlist *evlist, int timeout); > > > > > > struct evsel *evlist__id2evsel(struct evlist *evlist, u64 id); > > > -- > > > 2.17.1 > > > > > > -- - Arnaldo