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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AB61C433EF for ; Sat, 5 Mar 2022 19:51:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232259AbiCETvs (ORCPT ); Sat, 5 Mar 2022 14:51:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231834AbiCETvr (ORCPT ); Sat, 5 Mar 2022 14:51:47 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A72064D4; Sat, 5 Mar 2022 11:50:56 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F1261B80CA1; Sat, 5 Mar 2022 19:50:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BFEBAC004E1; Sat, 5 Mar 2022 19:50:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646509853; bh=zE8mY7gSZ94ep1kSuWQL2BU4MPCGeaZjsBead339r+A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LtIJ6kb3cOTmfja5IypACO5cXZ6Tq+dnIt3f6IG+FZ5Hn4skKQGJWRuvJ2v/PoytQ tU88U4Y8AKnl/lbabx6BMNmhpg+8WJoAI4KdjGWLXH5rEKUyiAeFXzC2J/ysMlJJXy rpCCpdtkjM8J0GJWd8g/N5hWezEyY+4giLB7TJRY= Date: Sat, 5 Mar 2022 20:50:42 +0100 From: Greg KH To: dann frazier Cc: stable@vger.kernel.org, Miao Xie , Valentin Schneider , Dietmar Eggemann , Peter Zijlstra , Ingo Molnar , Vincent Guittot , Barry Song , John Paul Adrian Glaubitz , Sergei Trofimovich , Anatoly Pugachev , Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCH 5.10+5.4 0/3] sched/topology: Fix missing scheduling domain levels Message-ID: References: <20220305164430.245125-1-dann.frazier@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220305164430.245125-1-dann.frazier@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 05, 2022 at 09:44:27AM -0700, dann frazier wrote: > The LTP cpuset_sched_domains test, authored by Miao Xie, fails on a Kunpeng920 > server that has 4 NUMA nodes: > https://launchpad.net/bugs/1951289 > > This does appear to be a real bug. /proc/schedstat displays 4 domain levels for > CPUs on 2 of the nodes, but only 3 levels for the others 2 (see below). > I assume this means the scheduler is making suboptimal decisions about > where to place/move processes. I'm not sure how to demonstrate that - but > open to suggestions if that evidence is important justification for stable. > > This is not a problem in current upstream kernels, so I bisected and found > that the first patch here fixes it. I can't tell from the commit message > if fixing this case was Valentin's intent, or just a happy side-effect of the > set conversion. The other two patches fix regressions introduced by the first. > All cherry-pick cleanly back to 5.10.y and 5.4.y. This platform easily > reproduces the problem Dietmar's fix addresses. I don't have hardware to test > the ia64 fix. > > Note: This also impacts earlier stable trees, but require some minor porting, > so I'll submit fixes for those separately. > > Here's a comparison of /proc/schedstat before & after applying these > fixes: Thanks, now queued up. greg k-h