Date: Wed, 29 Jun 2016 18:08:11 -0700 From: Colin Percival <cperciva@freebsd.org> To: Bryan Drewery <bdrewery@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r302288 - head/release/tools Message-ID: <a4733f5c-4dcf-2174-000f-347ad3114277@freebsd.org> In-Reply-To: <7a41dac2-87b8-c255-391d-fce3d57e835a@FreeBSD.org> References: <201606292356.u5TNuODh057121@repo.freebsd.org> <7a41dac2-87b8-c255-391d-fce3d57e835a@FreeBSD.org>
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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
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