From owner-svn-src-all@FreeBSD.ORG Sat Mar 20 15:32:30 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 09E78106566C; Sat, 20 Mar 2010 15:32:30 +0000 (UTC) (envelope-from kmatthew.macy@gmail.com) Received: from qw-out-2122.google.com (qw-out-2122.google.com [74.125.92.24]) by mx1.freebsd.org (Postfix) with ESMTP id 77A668FC18; Sat, 20 Mar 2010 15:32:29 +0000 (UTC) Received: by qw-out-2122.google.com with SMTP id 5so653028qwi.7 for ; Sat, 20 Mar 2010 08:32:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:reply-to:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=kKW/OMtM6DSWBAAWxws76B3cvdnM3sRrs0QJry8HBoM=; b=ZSTxOS9soGhUg7xGds42STV/ksHNYlZhdsIXxXDBbJQwlgSrc5SIi6NedU2ff0Rycc IW+QsPMkh+vzQ5abF6mq/hQSxoIuZ5F3q9zLV59x4y/Z1Lf9eeVJZUjLZTEnHlB1UeOI 3EmPDS/EYIUXA1WXt0Zs1EYxfvw7xn9jELMWM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:reply-to:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=P5D29nHGqHfhr3fUIetK9wk7NMsOkZwvO0K0r/kI9uaxYV62LNAZa6tH43XeCHNKKk rfS3tCy6HLHzKaueVL7qXemsHjnCMhoaEUFhde90D86bO2RC251byMlOt/DWtlqz2cGU lNPaNbv97YpDcatS5T2CQUg/0HeGieE2M/nag= MIME-Version: 1.0 Sender: kmatthew.macy@gmail.com Received: by 10.229.224.149 with SMTP id io21mr1101704qcb.94.1269099147867; Sat, 20 Mar 2010 08:32:27 -0700 (PDT) In-Reply-To: <20100320111013.GE1733@garage.freebsd.pl> References: <201003132141.o2DLfroC041203@svn.freebsd.org> <20100320111013.GE1733@garage.freebsd.pl> Date: Sat, 20 Mar 2010 07:32:27 -0800 X-Google-Sender-Auth: 03c37bc5120408e5 Message-ID: <82c4140e1003200832h116dee34p56022c100ff65b74@mail.gmail.com> From: "K. Macy" To: Pawel Jakub Dawidek Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r205132 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: kmacy@freebsd.org 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: Sat, 20 Mar 2010 15:32:30 -0000 On Sat, Mar 20, 2010 at 3:10 AM, Pawel Jakub Dawidek wrot= e: > On Sat, Mar 13, 2010 at 09:41:53PM +0000, Kip Macy wrote: >> Author: kmacy >> Date: Sat Mar 13 21:41:52 2010 >> New Revision: 205132 >> URL: http://svn.freebsd.org/changeset/base/205132 >> >> Log: >> =A0 Don't bottleneck on acquiring the stream locks - this avoids a massi= ve >> =A0 drop off in throughput with large numbers of simultaneous reads > > This is another[1] change we agreed (I hoped) to properly evaluate first > through zfs-code@opensolaris.org. > Hi pjd - I ran it by zfs-code@ a year ago. I never got any meaningful feedback. I'm not being flippant when I say that I would like you to interact with them. One thing you need to also bear in mind is that Opensolaris !=3D FreeBSD. I don't mean that in the phk "this is the wrong mailing list" sense, but rather the two have different behavioral properties. The deadlock that I had to track down by hand because you had disabled witness on ZFS locks occurred within 10 minutes on a modest web serving load and within 2 minutes under fsstress. It had been in ZFS quite some time when they finally patched it and yet it was a very serious problem on FreeBSD. Web serving throughput would drop from 2.5Gbps to a few hundred megabits per second without this change. I can only guess that sx locks do not behave the same as Solaris' mutexes to such a large extent that we get very different behaviors and you'll have to keep an open mind to local changes that cope with that fact. Thanks, Kip