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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 6FF40C43441 for ; Thu, 22 Nov 2018 01:50:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C02F206B2 for ; Thu, 22 Nov 2018 01:50:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C02F206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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 S2391606AbeKVM1j (ORCPT ); Thu, 22 Nov 2018 07:27:39 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:38439 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730718AbeKVM1j (ORCPT ); Thu, 22 Nov 2018 07:27:39 -0500 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 38A67AA5664AB; Thu, 22 Nov 2018 09:50:32 +0800 (CST) Received: from [127.0.0.1] (10.111.194.139) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.408.0; Thu, 22 Nov 2018 09:50:30 +0800 Subject: Re: perf tools: remove option --tail-synthesize ? To: Arnaldo Carvalho de Melo References: <89AC26A9-5A18-4608-8889-9C3C9C1C69D3@fb.com> <20181121131156.GG6248@kernel.org> CC: Song Liu , lkml , Jiri Olsa , Peter Zijlstra , "Kernel Team" From: "Wangnan (F)" Message-ID: Date: Thu, 22 Nov 2018 09:50:15 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20181121131156.GG6248@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.194.139] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Thank you. >> Thoughts? > > Wang, wdyt? > > - Arnaldo >