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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 D0011C43331 for ; Fri, 6 Sep 2019 22:06:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97E0C2081B for ; Fri, 6 Sep 2019 22:06:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lNgG4lbA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392213AbfIFWGW (ORCPT ); Fri, 6 Sep 2019 18:06:22 -0400 Received: from mail-ed1-f42.google.com ([209.85.208.42]:45933 "EHLO mail-ed1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392106AbfIFWGW (ORCPT ); Fri, 6 Sep 2019 18:06:22 -0400 Received: by mail-ed1-f42.google.com with SMTP id f19so7799286eds.12 for ; Fri, 06 Sep 2019 15:06:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=4Ctf2fCGCOyzuiCld+Wec4lg3Dv6DzWXv1MMXQpgIfE=; b=lNgG4lbAERn9xYOVosyYKY9R17VFg5Hw9a1IORhKLTCw/W4N+aLnHG2624Sivj+VL9 Kiu27MA8uqwkFTMuIZSrh5zSm2riJoPl4oFHDyBHqqDckuO14kE4sL86iXydIQZOknnK pDtRljNF/jN7ZM5zmg5INEj8lRBlDukXJcKS2Wztq0zbT77VQwIMv0ptUOJ8LfRD+DmF iQVwpPhkNYOeRe71WXff/30LfrYEQ1+d2O/39ZbptLH8pi933XhgK/C6+FG84sdQzTYk ebFgZEtZIgIeVibGQDFciYRVkVWUojyoq4jr0Phy+4HH6vY9ZpFMjMo+YJ/WOz66RLbC HqYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4Ctf2fCGCOyzuiCld+Wec4lg3Dv6DzWXv1MMXQpgIfE=; b=MUfQhwhhYMN3Iuijb86qo1FODi4ItAibCoGQTG7iNtp/Oen0p/qTptGaaelR2D+06V 6nLFkYKLPQTUj6N8DOSg7tKCrAEG6AEjdMN1kVQCY+ZTRKy4L+q9TWxQGZg5xKgNxGI1 SvwOYvJn4c/9MFJffnk+FX/6NuRL3FwGejvaS3cac/dbERPuNxfYUGeJysEa218ftm76 Q9xlJU42YbpJY5W+kQle1VCceodVRCvCf9OnWFKRpgusUPYLmHGp35DUiN3lUjH7te6B poI6jrFjJ8tjw140pSOnniVZhGZ9AAeNGJ90/knDj398SK2M7EZ22bmGPdtgn9e8OnSN Hd1A== X-Gm-Message-State: APjAAAV1ftrXUH/yjtZDcPVFL/rPZ6xUfV0IuV1RktYmbo9sCfJ2fz9P knX/sJc3BQQd6PlzbKuo4QHK5v7nE/IEMJ3+eus= X-Google-Smtp-Source: APXvYqw7378fSsZWAhyBZJyEz4vr/0uojIK/wo4v3MsbXH4nQixYOJzHd96CeAUf/jHjw+MacwiTSh4EU3n0EpVHYzw= X-Received: by 2002:a50:d903:: with SMTP id t3mr11827107edj.117.1567807580306; Fri, 06 Sep 2019 15:06:20 -0700 (PDT) MIME-Version: 1.0 References: <1A2AF5F768264E479963C4D8C015EB696C50C6BB@DLDEFFMIMP02EXC.intra.dlr.de> <20190905154115.mnid6rue65x6vvt6@linutronix.de> <1A2AF5F768264E479963C4D8C015EB696C51159F@DLDEFFMIMP02EXC.intra.dlr.de> In-Reply-To: <1A2AF5F768264E479963C4D8C015EB696C51159F@DLDEFFMIMP02EXC.intra.dlr.de> From: Austin Schuh Date: Fri, 6 Sep 2019 15:06:07 -0700 Message-ID: Subject: Re: Long latencies during disk-io To: Martin.Wirth@dlr.de Cc: bigeasy@linutronix.de, linux-rt-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Fri, Sep 6, 2019 at 11:48 AM wrote: > For the tracing, I at the moment have no idea how to set it up. I only did some > tracing which was triggered by cyclictest. But that won't help here... Modify your code to open up /sys/kernel/debug/tracing/tracing_on and write 0 to it when you detect a high latency event. I'd suggest opening up the file when the code starts and writing when the event happens, but opening and writing all at once would be fine. I've very successfully used that to catch events in the past. Austin