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 EDC94C001DF for ; Tue, 25 Jul 2023 13:32:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230211AbjGYNcP (ORCPT ); Tue, 25 Jul 2023 09:32:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230265AbjGYNcO (ORCPT ); Tue, 25 Jul 2023 09:32:14 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 062811BC2; Tue, 25 Jul 2023 06:32:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=cJS9hWdS3WIM11d6kg/J2cpVY/K0AghRcBxdtWBel3E=; b=fu+uGT2qcg8H3XiKFVWP5UKtUq lKTdMja9KLM/RBM3EcVilsF1p6x9bJYZyEu8mCJq15cab7zWZYLSH8YhSJkaxEU9CifjHcmYyyEZO Cf53hw9g1ptZIAbpS3kVqcJxy5W6LlO+BIHvpK8CEjL57HhwzJxe5xBN1J5V/aFKGzgONGBUkldOd ahHKi1y7acZIY4uAlNt/Kf784xjSInYAkfOjQ8OgNI//f0XwDKkMx9yjgysj7/lfDfPTogfHM5+tA NdyAbLHorlLqctEgX4rPYQT901Yl7uMHDgFYn16OELr/frraKQpiR1ToCCuHV5//3Y8ce15wO9r5E OJZUQz4Q==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qOI7x-004A0r-0c; Tue, 25 Jul 2023 13:31:01 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 42AC4300095; Tue, 25 Jul 2023 15:31:00 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 265B52CCD6AC0; Tue, 25 Jul 2023 15:31:00 +0200 (CEST) Date: Tue, 25 Jul 2023 15:31:00 +0200 From: Peter Zijlstra To: Ze Gao Cc: Ingo Molnar , Steven Rostedt , Namhyung Kim , Ian Rogers , Arnaldo Carvalho de Melo , Jiri Olsa , Mark Rutland , Masami Hiramatsu , Adrian Hunter , Alexander Shishkin , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Ze Gao Subject: Re: [RFC PATCH 1/3] sched, tracing: report task state in symbolic chars instead Message-ID: <20230725133100.GL3765278@hirez.programming.kicks-ass.net> References: <20230725072254.32045-1-zegao@tencent.com> <20230725072254.32045-2-zegao@tencent.com> <20230725083357.GA3765278@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Tue, Jul 25, 2023 at 06:53:07PM +0800, Ze Gao wrote: > > > @@ -232,7 +235,7 @@ TRACE_EVENT(sched_switch, > > > __array( char, prev_comm, TASK_COMM_LEN ) > > > __field( pid_t, prev_pid ) > > > __field( int, prev_prio ) > > > - __field( long, prev_state ) > > > + __field( char, prev_state ) > > > __array( char, next_comm, TASK_COMM_LEN ) > > > __field( pid_t, next_pid ) > > > __field( int, next_prio ) > > > > This is a format change and will likely break a ton of programs :/ > > BTW, could you help to point to any possible tools/programs that would > break other than perf/libtraceevent, because these two are the only > users I run into so far. Latencytop was the one breaking a few years ago, but there's a metric ton of sched_switch users out there, this is bound to generate pain. Steve, you remember what the status of all this was? at the time breaking this was considered on par with ABI breakage and we reverted or something. Is this still so?