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 17598C433EF for ; Thu, 10 Feb 2022 15:05:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243419AbiBJPFp (ORCPT ); Thu, 10 Feb 2022 10:05:45 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:46254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243394AbiBJPFi (ORCPT ); Thu, 10 Feb 2022 10:05:38 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C5B7C53; Thu, 10 Feb 2022 07:05:39 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DB9B861B03; Thu, 10 Feb 2022 15:05:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 50C73C340E5; Thu, 10 Feb 2022 15:05:37 +0000 (UTC) Date: Thu, 10 Feb 2022 10:05:35 -0500 From: Steven Rostedt To: Krzysztof Kozlowski Cc: Sebastian Andrzej Siewior , Ingo Molnar , Shuah Khan , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, joseph.salisbury@canonical.com, Shuah Khan Subject: Re: [PATCH v2] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT Message-ID: <20220210100535.01ad4978@gandalf.local.home> In-Reply-To: <429dd2fd-3ceb-6780-f970-4ea9b115388c@canonical.com> References: <20220210083356.11212-1-krzysztof.kozlowski@canonical.com> <546f147d-1682-fb92-42e5-7247dc19dcf1@canonical.com> <429dd2fd-3ceb-6780-f970-4ea9b115388c@canonical.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Feb 2022 15:13:15 +0100 Krzysztof Kozlowski wrote: > >> The implementation detail is that do_softirq() is in ifndef. > > > > So let me ask again. We have > > FUNC1="schedule" > > FUNC2="do_softirq" > > > > What is the purpose of this? Do you need FUNC2 when ksoftirqd is run or > > when softirqs are served? Not sure how scheduler_tick fits in all this. > > I guess this is more a question to the author of the test. Unless you > are now questioning the entire purpose of this test? The test is just a smoke test on function triggers. These two functions have various triggers attached to them to see if it causes any harm (the test was added after some strange bugs happened in the past). Now, if "_printk" worked, it suggests that I need to look into this test because I'm guessing _printk would never trigger during the test. The reason we picked schedule and do_softirq was to get triggers in different contexts (do_softirq was in the softirq context, and schedule is in the normal context). The reason I suggested to pick "schedule_tick" is because that should happen in the interrupt context. But if _printk worked, then it probably didn't test that part. But that's a different bug than what this patch is addressing. Reviewed-by: Steven Rostedt (VMware) And I need to add to my TODO list, to look at this test and probably rewrite. it. :-p -- Steve