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=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 757B0C48BDF for ; Tue, 15 Jun 2021 06:01:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4379061403 for ; Tue, 15 Jun 2021 06:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229539AbhFOGDW (ORCPT ); Tue, 15 Jun 2021 02:03:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:40468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229520AbhFOGDW (ORCPT ); Tue, 15 Jun 2021 02:03:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 35EE860720; Tue, 15 Jun 2021 06:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623736878; bh=6+Xsjc6mhzFwkeVtJlWg7rfSXLGzA8yfj6gPeHytIjk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HeClBzVnN5StT2aEIrpy6h6FjrvrEj6Hmq1BmbSTY5vL4TD0JLvVXKsP/JjWujddP Z9lfxC8bSyNgN25G59UHj5YC3GT4B6dUsR1dzC5AzxpzpoKysYhxTiZstURNolWlaB d8f5zF8NS6UNmQAHTqxkm7EuQvF+acDJJX24z4s8= Date: Tue, 15 Jun 2021 08:01:15 +0200 From: Greg KH To: Adam Edge Cc: "stable@vger.kernel.org" , "regressions@lists.linux.dev" Subject: Re: Regression after 5.7.19 causing major freezes on CPU loads Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jun 14, 2021 at 07:21:55PM +0000, Adam Edge wrote: > Hello, > > After I've upgraded from 5.7.11 (didn't have access to this machine for > about 10 months) to 5.12.10, I've noticed that anytime I used all my > cores to, for example, compile a project, the system would degrade > significantly in performance and applications would start to stutter. > Compiles are also about 3-4x slower on kernels with the regression vs. > without. After debugging this for the past 24 hours or so, I've narrowed > it down to a change between 5.7.19 and 5.8.1. Sadly, bisect does not > help, because trying to run any of the 5.8 RC kernels causes the kernel > to be stuck before init, without any apparent errors on the screen (and > I don't have a serial cable to dump the kernel output to). I'm listing > all the information I know and my system information below. > > Reproduction steps (dunno if this helps, but): > 1. Boot with kernel with the regression > 2. Do something that uses all cores, like compiling the Linux kernel > 3. Observe long compile times and stuttering applications (which doesn't > happen even on full load with a working kernel) > > Regression between kernel versions: > 5.7 - working > 5.7.11 - working > 5.7.19 - working > 5.8.1 - broken > 5.8.18 - broken > 5.12.10 - broken > 8ecfa36cd4db3275bf3b6c6f32c7e3c6bb537de2 (master on 2021-06-13) - broken Can you use 'git bisect' to track down the commit that caused the problem? thanks, greg k-h