From owner-svn-src-all@freebsd.org Mon Aug 3 13:11:39 2015 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A1DA89B2760; Mon, 3 Aug 2015 13:11:39 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 6A7862E9; Mon, 3 Aug 2015 13:11:37 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua [212.40.38.100]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id QAA22526; Mon, 03 Aug 2015 16:11:35 +0300 (EEST) (envelope-from avg@FreeBSD.org) Received: from localhost ([127.0.0.1]) by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD)) id 1ZMFWg-000BeF-N8; Mon, 03 Aug 2015 16:11:34 +0300 Message-ID: <55BF6863.8000103@FreeBSD.org> Date: Mon, 03 Aug 2015 16:10:59 +0300 From: Andriy Gapon User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Scott Long CC: src-committers@FreeBSD.org, svn-src-all@FreeBSD.org, svn-src-head@FreeBSD.org Subject: Re: svn commit: r284297 - in head: cddl/contrib/opensolaris/cmd/lockstat sys/kern sys/sys References: <201506121001.t5CA1PTm089721@svn.freebsd.org> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Aug 2015 13:11:39 -0000 On 26/07/2015 23:27, Scott Long wrote: > >> On Jun 12, 2015, at 4:01 AM, Andriy Gapon wrote: >> >> Author: avg >> Date: Fri Jun 12 10:01:24 2015 >> New Revision: 284297 >> URL: https://svnweb.freebsd.org/changeset/base/284297 >> >> Log: >> several lockstat improvements >> >> 0. For spin events report time spent spinning, not a loop count. >> While loop count is much easier and cheaper to obtain it is hard >> to reason about the reported numbers, espcially for adaptive locks >> where both spinning and sleeping can happen. >> So, it's better to compare apples and apples. >> > > This causes spinning to be exceptionally more expensive just by having > KDTRACE_HOOKS enabled, whether or not Dtrace is actually in use. It > makes it undesirable to deploy with Dtrace by default since it impacts > performance. Is there a way to make the expensive collection optional, > or only enable when dtrace is using the lockstat module? Also have you > seen the other recent performance complaint related to this commit? Sorry for the trouble. Commit https://svnweb.freebsd.org/changeset/base/285704 should have fixed the problem. Could you please check if that's so? Thanks. -- Andriy Gapon