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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 C7C0DC43441 for ; Thu, 22 Nov 2018 09:03:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94FDE20820 for ; Thu, 22 Nov 2018 09:03:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94FDE20820 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393335AbeKVTmM (ORCPT ); Thu, 22 Nov 2018 14:42:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53630 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731655AbeKVTmL (ORCPT ); Thu, 22 Nov 2018 14:42:11 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3E7AE80F79; Thu, 22 Nov 2018 09:03:38 +0000 (UTC) Received: from krava (unknown [10.43.17.92]) by smtp.corp.redhat.com (Postfix) with SMTP id B08D663F88; Thu, 22 Nov 2018 09:03:36 +0000 (UTC) Date: Thu, 22 Nov 2018 10:03:35 +0100 From: Jiri Olsa To: "Wangnan (F)" Cc: Arnaldo Carvalho de Melo , Song Liu , lkml , Jiri Olsa , Peter Zijlstra , Kernel Team Subject: Re: perf tools: remove option --tail-synthesize ? Message-ID: <20181122090335.GA15953@krava> References: <89AC26A9-5A18-4608-8889-9C3C9C1C69D3@fb.com> <20181121131156.GG6248@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 22 Nov 2018 09:03:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 22, 2018 at 09:50:15AM +0800, Wangnan (F) wrote: > > > On 2018/11/21 21:11, Arnaldo Carvalho de Melo wrote: > > Em Wed, Nov 21, 2018 at 07:45:28AM +0000, Song Liu escreveu: > >> Hi, > >> > >> I found perf-record --tail-synthesize without --overwrite breaks symbols > >> for perf-script, perf-report, etc. For example: > >> > >> [root@]# ~/perf record -ag --tail-synthesize -- sleep 1 > >> [ perf record: Woken up 1 times to write data ] > >> [ perf record: Captured and wrote 1.129 MB perf.data (3531 samples) ] > >> [root@]# ~/perf script | head > >> swapper 0 [000] 1250675.051971: 1 cycles:ppp: > >> ffffffff81009e15 [unknown] ([unknown]) > >> ffffffff81196b19 [unknown] ([unknown]) > >> ffffffff81196579 [unknown] ([unknown]) > >> ffffffff81110ca7 [unknown] ([unknown]) > >> ffffffff81a01f4a [unknown] ([unknown]) > >> ffffffff81a017bf [unknown] ([unknown]) > >> ffffffff8180e17a [unknown] ([unknown]) > >> > >> perf-record with --overwrite does NOT have this issue. > >> > >> After digging into this, I found this issue is introduced by commit > >> a73e24d240bc136619d382b1268f34d75c9d25ce. > >> > >> Reverting this commit does fix this issue. However, on a second thought, > >> I feel it is probably better just drop --tail-synthesize, as it doesn't > >> make much sense without --overwrite. All we need is to do tail_synthesize > >> when --overwrite is set. > >> > > Some cases we use --overwrite without --tail-synthesize. How about setting > --tail-synthesize when selecting --overwrite by default, throw a warning > when --overwrite is not set and leave a --no-tail-synthesize option? sounds good to me thanks, jirka