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=-4.1 required=3.0 tests=BAYES_00,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 C0746C433E0 for ; Mon, 3 Aug 2020 11:45:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D3A02065C for ; Mon, 3 Aug 2020 11:45:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jzMX2BcU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726509AbgHCLpR (ORCPT ); Mon, 3 Aug 2020 07:45:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726433AbgHCLlX (ORCPT ); Mon, 3 Aug 2020 07:41:23 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3AF6C06174A for ; Mon, 3 Aug 2020 04:41:16 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id a21so38254505ejj.10 for ; Mon, 03 Aug 2020 04:41:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=0+NO3ztULAIrGvrz5D9Y/HzaMZX3dT9yOjYO20mJWFE=; b=jzMX2BcUcYomvDCitAj65HNQx2dB7wG/CeGganhYRU7W0Sm6ACLMm040YEkm9soXV1 1wZ8ZjKgHe/uNZCoeb5D1nMODexXPlx3ohsylTZZqKqCMOgqmTPHxAEVaPUD7jpVI2Rm DV494Tp8SsExOoAqi+pMyjs8DfMl80Zz7HP42mLmIVmPhlLvSKayu00PtNZDUlvjNow0 KPSfzWT3b9xSsI6Yy6vnyxR8xQ/eDGjC5ZYr2vWR+bNvPHluGZRiFzHuUnofI3u7dJyS 1yJrkXF8Zalcf06YxzMaz91W1RGFU5uVfjmVsZAB+CmREqL88U4yfOS9PWq3QigUc4jl mZ1g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=0+NO3ztULAIrGvrz5D9Y/HzaMZX3dT9yOjYO20mJWFE=; b=sVVA1w52MjcM8BSkC+uc4S19vmp3LR2csgYT5OIOtsJUYk2UlI4TZuAzWreyNhMqV/ +4u8/Uo7E/BpobYxqJFgcFSACBIicQaV7AJ3VGc5ZDHVbB5+hwT3SAs/FEp86Ny5NM3y 4OLqmLm2DmD/CfhmMcxvq2RsnQqtXIlhHJRQuhOz+dGt3FWykJbr9y2L0S4gBUX9PT/L rCkbxqtbwC40ViF/m9A4w7nZggyD78c9dvlPpkgNj2k9+0Z0ZXV4seTtDgvP8VMA3myJ V6NoJITz4p6LhHsoPbCKDRjuKcV98ENY452HVZGaCIIfdVwvHmxJikI7L4k6yiC4LauN 1RpQ== X-Gm-Message-State: AOAM532YA/QPIXwNsjW4tEASIrEFV4jxlVpAOk1vONiDvjEYGZ8x3aNC P896v+Wv6G2mqScEgS+O76Y= X-Google-Smtp-Source: ABdhPJzJkwmJEmCwN333UYXomgbiIRREmBIPLG34327fzVLIHjLggxQ94KTrrbw/uHE/S0NcN5chQg== X-Received: by 2002:a17:906:a2c2:: with SMTP id by2mr15793481ejb.86.1596454875500; Mon, 03 Aug 2020 04:41:15 -0700 (PDT) Received: from skbuf ([188.26.57.97]) by smtp.gmail.com with ESMTPSA id d25sm15916774edr.78.2020.08.03.04.41.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Aug 2020 04:41:14 -0700 (PDT) Date: Mon, 3 Aug 2020 14:41:12 +0300 From: Vladimir Oltean To: Thomas Gleixner Cc: Kurt Kanzenbach , Alison Wang , catalin.marinas@arm.com, will@kernel.org, paulmck@kernel.org, mw@semihalf.com, leoyang.li@nxp.com, vladimir.oltean@nxp.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Anna-Maria Gleixner , Peter Zijlstra Subject: Re: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting Message-ID: <20200803114112.mrcuupz4ir5uqlp6@skbuf> References: <20200729033934.22349-1-alison.wang@nxp.com> <877dumbtoi.fsf@kurt> <20200729094943.lsmhsqlnl7rlnl6f@skbuf> <87mu3ho48v.fsf@kurt> <20200730082228.r24zgdeiofvwxijm@skbuf> <873654m9zi.fsf@kurt> <87lfiwm2bj.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lfiwm2bj.fsf@nanos.tec.linutronix.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, On Mon, Aug 03, 2020 at 12:49:36PM +0200, Thomas Gleixner wrote: > Kurt, > > Kurt Kanzenbach writes: > > On Thu Jul 30 2020, Vladimir Oltean wrote: > > OK. I've reproduced it on a Marvell Armada SoC with v5.6 mainline. See > > splats below. Running with irq time accounting enabled, kills the > > machine immediately. However, I'm not getting the possible deadlock > > warnings in 8250 as you did. So that might be unrelated. > > > > Unfortunately I have no idea what to debug here. > > lets look at the facts we have so far. > > 1) When irq accounting is disabled, RT throttling kicks in as > expected. > > 2) With irq accounting the RT throttler does not kick in and the RCU > stall/lockups happen. > > Not much, but there is clearly interaction between irq time accounting > and scheduler accounting. > > Can you please reduce /proc/sys/kernel/sched_rt_runtime_us in steps of > 50000? At least in theory, reduction should bring the throttling back. > > Thanks, > > tglx > We already know from my original report that reducing sched_rt_runtime_us to 80% (800000) gives us a stable system. https://lkml.org/lkml/2020/6/4/1062 What is this telling us? Thanks, -Vladimir