From owner-svn-src-head@FreeBSD.ORG Wed Mar 16 19:51:58 2011 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9E3E1106564A; Wed, 16 Mar 2011 19:51:58 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from mail-qw0-f54.google.com (mail-qw0-f54.google.com [209.85.216.54]) by mx1.freebsd.org (Postfix) with ESMTP id 345F88FC13; Wed, 16 Mar 2011 19:51:57 +0000 (UTC) Received: by qwc9 with SMTP id 9so1740740qwc.13 for ; Wed, 16 Mar 2011 12:51:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:in-reply-to:references:from :date:x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; bh=zJOyyy7pig2SS7eI8c53RwhjsMl+buCfYzTFQn7aAUY=; b=NSiCGka4Ulef2+/gPZQRD5GlVsU0F1PN2jvBf4bVmNiYvDL9Lxlu0e74vu707qzWm4 KIuNATkp7bTf9N/pVcIeXKoHw1oYmMnq/rqLbu92ehI/VS4kfw5pAlrfJBTWwMKhlcH/ 0chkCaeBr4YnpeEbWQzkI1o9FUfki7grf6SXc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=P4s9QlpuSWKEGdEd3ckWHdca+kOtVN5zqZw2TYxESv4SDPQdFPRgcBmxyHOj/Ze6Cw /627JRVfvLMv6jptLOHZyn6LnQ0tpULpDCEayryeWju5HtbyfpSuA801Y4wsqQxqxx44 dG16rsIhriNFY+nv18dIEvAd7GH7d5EI1vmOU= Received: by 10.229.107.15 with SMTP id z15mr408398qco.99.1300305117301; Wed, 16 Mar 2011 12:51:57 -0700 (PDT) MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.229.78.193 with HTTP; Wed, 16 Mar 2011 12:51:17 -0700 (PDT) In-Reply-To: <20110316174642.GB6367@freebsd.org> References: <201103161622.p2GGMxNp097642@svn.freebsd.org> <20110316174642.GB6367@freebsd.org> From: Ivan Voras Date: Wed, 16 Mar 2011 20:51:17 +0100 X-Google-Sender-Auth: DeBmTJyNxMyy_sFlF1ZUyUc576I Message-ID: To: Roman Divacky Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r219699 - head/sys/kern X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Mar 2011 19:51:58 -0000 On 16 March 2011 18:46, Roman Divacky wrote: > > On Wed, Mar 16, 2011 at 04:22:59PM +0000, Ivan Voras wrote: > > Author: ivoras > > Date: Wed Mar 16 16:22:59 2011 > > New Revision: 219699 > > URL: http://svn.freebsd.org/changeset/base/219699 > > > > Log: > > =C2=A0 The hardware has caught up; improvements are now observed even a= t 128, > > =C2=A0 but stay conservative and bump read_max to "only" 64 (it will pr= obably be > > =C2=A0 a good idea to increase this to 128 after the next major release= ). > > how did you measure this? Specifically for this commit: my desktop 2xSATA 7200 RPM drives, gmirror, single read "dd" stream, bs=3D1m. (Are there any ready read multi-stream read tests which are not trivial i.e. they start from different positions in the file?) results: read_max=3D32 -> 78 MB/s read_max=3D64 -> 136 MB/s read_max=3D128 -> 141 MB/s I'm the one who previously bumped read_max from 8 to 32 about a year ago, based on tests under an (otherwise idle, naturally) VMWare cluster on a FC SAN, and a similar point of saturation was at read_max=3D64. Now it is at 128 with raw hardware. Maybe it should be tuned at 2^(major_freebsd_version-2) :) (as for safety & stability, I've put 2-3 new web servers in production this year with read_max=3D128 irregardless of this commit. It's stable).