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authorcperciva <cperciva@FreeBSD.org>2016-06-29 23:56:24 +0000
committercperciva <cperciva@FreeBSD.org>2016-06-29 23:56:24 +0000
commit94125daa1728385d847e6f0dccf14041d864a3ca (patch)
tree9b5a9a57ce6de7356f595fd950b6d26095511acc /release
parent62a7c9548d707560ada6d9c2b84ee92a12943f4c (diff)
downloadFreeBSD-src-94125daa1728385d847e6f0dccf14041d864a3ca.zip
FreeBSD-src-94125daa1728385d847e6f0dccf14041d864a3ca.tar.gz
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
Diffstat (limited to 'release')
-rw-r--r--release/tools/ec2.conf5
1 files changed, 0 insertions, 5 deletions
diff --git a/release/tools/ec2.conf b/release/tools/ec2.conf
index 5f0e868..d22c9b0 100644
--- a/release/tools/ec2.conf
+++ b/release/tools/ec2.conf
@@ -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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