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_PASS autolearn=ham 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 AE18CC004D2 for ; Tue, 2 Oct 2018 13:57:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BD812064A for ; Tue, 2 Oct 2018 13:57:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BD812064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731447AbeJBUlB (ORCPT ); Tue, 2 Oct 2018 16:41:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47564 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727690AbeJBUlA (ORCPT ); Tue, 2 Oct 2018 16:41:00 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B4D5E88313; Tue, 2 Oct 2018 13:57:30 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-55.bos.redhat.com [10.18.17.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0CABE26DC4; Tue, 2 Oct 2018 13:57:29 +0000 (UTC) Subject: Re: [PATCH 0/5] locking/lockdep: Improve lockdep performance To: Ingo Molnar Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , linux-kernel@vger.kernel.org, Thomas Gleixner References: <1538157201-29173-1-git-send-email-longman@redhat.com> <20181002090652.GC116695@gmail.com> From: Waiman Long Organization: Red Hat Message-ID: <25661edf-2882-7019-1ef4-d79393f239ce@redhat.com> Date: Tue, 2 Oct 2018 09:57:29 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20181002090652.GC116695@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 02 Oct 2018 13:57:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/02/2018 05:06 AM, Ingo Molnar wrote: > * Waiman Long wrote: > >> Enabling CONFIG_LOCKDEP and other related debug options will greatly >> reduce system performance. This patchset aims to reduce the performance >> slowdown caused by the lockdep code. >> >> Patch 1 just removes an inline function that wasn't used. >> >> Patches 2 and 3 are minor twists to optimize the code. >> >> Patch 4 makes class->ops a per-cpu counter. >> >> Patch 5 moves the lock_release() call outside of a lock critical section. >> >> Parallel kernel compilation tests (make -j <#cpu>) were performed on >> 2 different systems: >> >> 1) an 1-socket 22-core 44-thread Skylake system >> 2) a 4-socket 72-core 144-thread Broadwell system >> >> The build times with pre-patch and post-patch debug kernels were: >> >> System Pre-patch Post-patch %Change >> ------ --------- ---------- ------- >> 1-socket 8m53.9s 8m41.2s -2.4% >> 4-socket 7m27.0s 5m31.0s -26% >> >> I think it is the last 2 patches that yield most of the performance >> improvement. > Impressive speedup! > > Mind including the non-lockdep numbers as well, for reference? > > Thanks, > > Ingo OK, I will include the non lockdep number for comparison. However the debug kernel has other debugging code enabled as well so the slowdown won't be just for the enabling of lockdep. -Longman