Date: Wed, 29 Jun 2016 23:56:24 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r302288 - head/release/tools Message-ID: <201606292356.u5TNuODh057121@repo.freebsd.org>
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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. Reverts: r286063 Approved by: re (gjb) MFC after: 2 weeks Relnotes: Improved disk throughput on EC2 Modified: head/release/tools/ec2.conf Modified: head/release/tools/ec2.conf ============================================================================== --- head/release/tools/ec2.conf Wed Jun 29 23:33:44 2016 (r302287) +++ head/release/tools/ec2.conf Wed Jun 29 23:56:24 2016 (r302288) @@ -72,11 +72,6 @@ vm_extra_pre_umount() { # nodes, but apply the workaround just in case. echo 'hw.broken_txfifo="1"' >> ${DESTDIR}/boot/loader.conf - # Some EC2 instances suffer a significant (~40%) reduction in - # throughput when using blkif indirect segment I/Os. Disable this - # by default for now. - echo 'hw.xbd.xbd_enable_indirect="0"' >> ${DESTDIR}/boot/loader.conf - # Some EC2 instances run on a version of Xen which has a bug relating # to the migration of MSI-X interrupts; this is visible as SR-IOV # networking (aka. "EC2 Enhanced Networking") not being able to pass
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