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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 88917C433E0 for ; Fri, 29 May 2020 13:31:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F3EF20723 for ; Fri, 29 May 2020 13:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727080AbgE2NbJ (ORCPT ); Fri, 29 May 2020 09:31:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726593AbgE2NbJ (ORCPT ); Fri, 29 May 2020 09:31:09 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A675C03E969; Fri, 29 May 2020 06:31:09 -0700 (PDT) Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1jef6J-0005Dk-CF; Fri, 29 May 2020 15:31:07 +0200 Date: Fri, 29 May 2020 15:31:07 +0200 From: Sebastian Andrzej Siewior To: Michael Nazzareno Trimarchi Cc: LKML , linux-rt-users@vger.kernel.org Subject: Re: linux-rt stall on imx6dl on patch-5.4.22-rt13.patch Message-ID: <20200529133107.y65eta5btvgpk6pu@linutronix.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-05-29 10:08:01 [+0200], Michael Nazzareno Trimarchi wrote: > Hi all Hi, > I get this stack trace > echo 3 > /proc/sys/vm/drop_caches chrt -f 99 sysbench --test=cpu --num-threads=2 > > First of all, I need to know that if it is a valid use case because > was raised by the testing team and > how can I start and where to take a look at it Assuming that there is a `;' in front of `chrt' then I wouldn't be surprised. You are basically keeping two CPUs busy with sysbench at RT priority and then wondering why the system isn't making any progress. If it wouldn't be for the RT throttler, you might not even see any output and box hardware would appear be dead. > Best Regards > Michael > > [ 161.709260] 001: sh (480): drop_caches: 3 > [ 180.234358] 001: sched: RT throttling activated > [ 180.283363] 001: fec 2188000.ethernet eth0: MDIO read timeout > [ 180.283406] 001: ------------[ cut here ]------------ > [ 180.283416] 001: WARNING: CPU: 1 PID: 133 at > drivers/net/phy/phy.c:716 phy_er > > ror+0x24/0x64 > [ 180.283460] 001: Modules linked in: > [ 180.283473] 001: CPU: 1 PID: 133 Comm: kworker/1:2 Tainted: G > W This is hard to read. Especially later in that mail. In future please try to not cut the lines. Sebastian