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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no 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 64C5DC4743D for ; Tue, 8 Jun 2021 17:39:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4576D6128E for ; Tue, 8 Jun 2021 17:39:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233536AbhFHRln (ORCPT ); Tue, 8 Jun 2021 13:41:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:36026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232376AbhFHRlm (ORCPT ); Tue, 8 Jun 2021 13:41:42 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DE94861287; Tue, 8 Jun 2021 17:39:47 +0000 (UTC) Date: Tue, 8 Jun 2021 13:39:46 -0400 From: Steven Rostedt To: Daniel Bristot de Oliveira Cc: linux-kernel@vger.kernel.org, Phil Auld , Sebastian Andrzej Siewior , Kate Carcia , Jonathan Corbet , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexandre Chartre , Clark Willaims , John Kacur , Juri Lelli , linux-doc@vger.kernel.org Subject: Re: [PATCH V3 8/9] tracing: Add osnoise tracer Message-ID: <20210608133946.52eb7859@oasis.local.home> In-Reply-To: References: <20210604172803.527aa070@oasis.local.home> X-Mailer: Claws Mail 3.17.3 (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 Tue, 8 Jun 2021 19:17:55 +0200 Daniel Bristot de Oliveira wrote: > On 6/4/21 11:28 PM, Steven Rostedt wrote: > >> + /* > >> + * This is an evidence of race conditions that cause > >> + * a value to be "discounted" too much. > >> + */ > >> + if (duration < 0) > >> + pr_err("int safe negative!\n"); > > Probably want to have this happen at most once a run. If something were > > to break, I don't think we want this to live lock the machine doing > > tons of prints. We could have a variable stored on the > > osnoise_variables that states this was printed. Check that variable to > > see if it wasn't printed during a run (when current_tracer was set), > > and print only once if it is. > > I created a "bool tainted" variable, that is set true if any problem with time() > related functions happen. I will pr_warn that there is a problem on _start(), > but also print this info at the top of the tracer header, so it is clear also > from the trace output. > > Thoughts? > Or perhaps have that pr_err() actually be written into the trace buffer? You can use trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_, "string"); without it triggering that nasty trace_printk() notice ;-) -- Steve