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 0630AC433EF for ; Thu, 10 Feb 2022 05:00:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232536AbiBJFAJ (ORCPT ); Thu, 10 Feb 2022 00:00:09 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:39642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbiBJFAH (ORCPT ); Thu, 10 Feb 2022 00:00:07 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 275061F7; Wed, 9 Feb 2022 21:00:08 -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 ams.source.kernel.org (Postfix) with ESMTPS id 53CF8B80E19; Thu, 10 Feb 2022 05:00:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49067C004E1; Thu, 10 Feb 2022 05:00:05 +0000 (UTC) Date: Thu, 10 Feb 2022 00:00:03 -0500 From: Steven Rostedt To: Krzysztof Kozlowski Cc: Ingo Molnar , Shuah Khan , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, joseph.salisbury@canonical.com Subject: Re: [PATCH] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT Message-ID: <20220210000003.6b6142f9@gandalf.local.home> In-Reply-To: <20220209162430.286578-1-krzysztof.kozlowski@canonical.com> References: <20220209162430.286578-1-krzysztof.kozlowski@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 Wed, 9 Feb 2022 17:24:30 +0100 Krzysztof Kozlowski wrote: > The PREEMPT_RT patchset does not use soft IRQs thus trying to filter for > do_softirq fails for such kernel: > > echo do_softirq > ftracetest: 81: echo: echo: I/O error > > Choose some other externally visible function for the test. > > Signed-off-by: Krzysztof Kozlowski > > --- > > I understand that the failure does not exist on mainline kernel (only > with PREEMPT_RT patchset) but the change does not harm it. > > If it is not suitable alone, please consider it for RT patchset. > --- > .../selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc > index e96e279e0533..1d0c7601865f 100644 > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc > @@ -19,7 +19,7 @@ fail() { # mesg > > FILTER=set_ftrace_filter > FUNC1="schedule" > -FUNC2="do_softirq" > +FUNC2="_printk" The problem with the above, is that it is not guaranteed to trigger (and probably will not), where as the do_softirq is. The filtering is suppose to trace something that actually happens. How about using: scheduler_tick ? -- Steve > > ALL_FUNCS="#### all functions enabled ####" >