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authorcperciva <cperciva@FreeBSD.org>2015-07-30 04:01:00 +0000
committercperciva <cperciva@FreeBSD.org>2015-07-30 04:01:00 +0000
commit84ed76c8118e483121b0f2ce0924a7f50c9bee92 (patch)
tree17b26e0f733e7b23c95ef2bfeca77e509071909e /release
parentd40e2b99300c55d54e6d9ce8e2de858398fdc450 (diff)
downloadFreeBSD-src-84ed76c8118e483121b0f2ce0924a7f50c9bee92.zip
FreeBSD-src-84ed76c8118e483121b0f2ce0924a7f50c9bee92.tar.gz
Disable blkif indirect segment I/Os in EC2 by default due to performance
issues on some EC2 instance types. Users may want to experiment with removing this from loader.conf and measuring the performance impact on the EC2 instances they are using.
Diffstat (limited to 'release')
-rw-r--r--release/tools/ec2.conf5
1 files changed, 5 insertions, 0 deletions
diff --git a/release/tools/ec2.conf b/release/tools/ec2.conf
index 9472ec5..557e602 100644
--- a/release/tools/ec2.conf
+++ b/release/tools/ec2.conf
@@ -70,6 +70,11 @@ 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
+
# The first time the AMI boots, the installed "first boot" scripts
# should be allowed to run:
# * ec2_configinit (download and process EC2 user-data)
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