From owner-svn-src-all@freebsd.org Thu Jun 30 01:08:53 2016 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 C3182B85541 for ; Thu, 30 Jun 2016 01:08:53 +0000 (UTC) (envelope-from bounces+73574-8822-svn-src-all=freebsd.org@sendgrid.net) Received: from o1.l99.sendgrid.net (o1.l99.sendgrid.net [198.37.153.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 538E028F4 for ; Thu, 30 Jun 2016 01:08:53 +0000 (UTC) (envelope-from bounces+73574-8822-svn-src-all=freebsd.org@sendgrid.net) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.info; h=subject:to:references:from:mime-version:in-reply-to:content-type:content-transfer-encoding; s=smtpapi; bh=te6roGlD8rlrivdNIUEW3nFkS3A=; b=fCWci/y7zX7tmsu2o9 E1PDJNmW/syL12USwrZ3NrB1cdvdCt+OTtpLe0NclwJzkKOnbEE85TjIkWIlbLiR O8rbQp9MdoDCq9RqKfXDiCUWLMWLzY0V6tfMpNnpxACidwXnUvrwcGWk8ugD2rse Ne2bMg/Wccitl2Ihonk3IatvY= Received: by filter0465p1mdw1.sendgrid.net with SMTP id filter0465p1mdw1.27772.577470FC43 2016-06-30 01:08:12.636547761 +0000 UTC Received: from mail.tarsnap.com (ec2-54-86-246-204.compute-1.amazonaws.com [54.86.246.204]) by ismtpd0003p1iad1.sendgrid.net (SG) with ESMTP id A8H9byljT_SZ4sNV8gwDvQ for ; Thu, 30 Jun 2016 01:08:12.701 +0000 (UTC) Received: (qmail 13813 invoked from network); 30 Jun 2016 01:07:25 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by ec2-107-20-205-189.compute-1.amazonaws.com with ESMTP; 30 Jun 2016 01:07:25 -0000 Received: (qmail 97416 invoked from network); 30 Jun 2016 01:08:11 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by clamshell.daemonology.net with SMTP; 30 Jun 2016 01:08:11 -0000 Subject: Re: svn commit: r302288 - head/release/tools To: Bryan Drewery , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201606292356.u5TNuODh057121@repo.freebsd.org> <7a41dac2-87b8-c255-391d-fce3d57e835a@FreeBSD.org> From: Colin Percival Message-ID: Date: Wed, 29 Jun 2016 18:08:11 -0700 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <7a41dac2-87b8-c255-391d-fce3d57e835a@FreeBSD.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SG-EID: A6W2xSVPHetogaU8rnzccWwgBYtN+QvIzXyjfe/10PFsO+zhKUVjcuaWIUgL4Af2XzWQqGIfkpRA/s XPe0ngMYuev4tE6b3DKTITCUVaupB7csr5BLYPbyep1JoVk01sfRsNZVvWB4Ksueo00EbXJho/plgP Y4shnHCcYTl9/+FjmHGksJAlGGUoOb9kdcH2p5e1hd4I4AJ+++ke+MZhZ3M5Qtkf8CTuZgkIiu2i4m A= X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.22 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: Thu, 30 Jun 2016 01:08:53 -0000 On 06/29/16 17:01, Bryan Drewery wrote: > On 6/29/2016 4:56 PM, Colin Percival wrote: >> Author: cperciva >> Date: Wed Jun 29 23:56:24 2016 >> New Revision: 302288 >> URL: https://svnweb.freebsd.org/changeset/base/302288 >> >> Log: >> Enable indirect segment I/Os by default in the Xen blkfront driver when >> running on EC2. Due to improvements in EC2, the performance penalty which >> was present on some EC2 instances no longer exists, and enabling this >> feature now consistently yields ~20% higher throughput with equal or lower >> latency. > > Does this rely on any driver updates / is it safe to make the same > change on my existing 10.2 system? The relevant driver code is only in 10.3 and later. I'm not absolutely certain if already-running EC2 instances have the EC2 performance fix, either; you might need to launch a new instance in order to be guaranteed of the performance benefits. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid