svn commit: r302288 - head/release/tools

[Bryan Drewery]

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?

>   
>   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
> 


-- 
Regards,
Bryan Drewery

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