Comments on: What is SR-IOV?

By: Sumesh.J.K

Sumesh.J.K — Wed, 05 Oct 2011 05:08:00 +0000

Informative blog on SR-IOV

By: slowe

slowe — Fri, 21 Jan 2011 02:23:25 +0000

Brian, also great information—thank you!

By: Brian Johnson

Brian Johnson — Wed, 19 Jan 2011 20:53:47 +0000

To show the potential of SR-IOV in a virtual environment
take a look at Patrick’s summary of an IBM report on SPECvirt_2010
results. IBM* Releases SR-IOV Performance on Red Hat* KVM with
Intel® Gigabit ET Server Adapter
http://communities.intel.com/community/wired/blog/2010/12/12/ibm-releases-sr-iov-performance-on-red-hat-kvm-with-intel-gigabit-et-server-adapter
Another resource to show the value of SR-IOV can be found on the
SPECvirt_2010 benchmark results page.
http://www.spec.org/virt_sc2010/results/specvirt_sc2010_perf.html
IBM just posted in Dec 2010 results of 5466.58@336VMs using the
Intel(R) Ethernet Controller X520 with SR-IOV vs. 778@48VMs as a
maximum without SR-IOV on 1Gb. Yes, this compares 10Gb vs. 1Gb but
if you read the IBM white paper that Patrick references you will
see that the 1Gb non-SR-IOV results were about as much performance
you can get regardless of the pipe size. They show that by using
SR-IOV in SPECvirt_2010 they see a performance advantage over
non-SR-IOV, even on 1Gb. I hope this provides some additional
information regarding the benefits that can be seen when SR-IOV is
used in a virtual environment. Brian Johnson – Intel Corp.

By: slowe

slowe — Wed, 19 Jan 2011 20:43:15 +0000

Good information—thanks Patrick!

By: Patrick

Patrick — Wed, 19 Jan 2011 20:15:06 +0000

From what I’ve read in the MR-IOV spec, you would expect about the same performance with MR-IOV as it is still a direct-assignment technology. Just a lot more complicated than SR-IOV (which is pretty complicated itself).

For those still interested in learning about SR-IOV, there is an update to the SR-IOV Primer doc I just finished available here:
http://communities.intel.com/community/wired/blog/2011/01/19/come-and-get-it-sr-iov-primer-document-updated
as well as a littel 10 minute video I did with some PowerPoint voodoo:
http://communities.intel.com/community/wired/blog/2010/09/07/sr-iov-explained

By: slowe

slowe — Fri, 31 Dec 2010 02:09:07 +0000

Robert, thanks for your comment. I’m glad to see you clearly state the relationship between the M81KR and SR-IOV; all I’ve been able to get is “it’s SR-IOV compliant,” which doesn’t really answer the question of whether or not it actually uses SR-IOV (which we know now that it doesn’t).

Anjali, SR-IOV and IOMMU are two distinct (but slightly related) technologies, so I’m not sure that a performance comparison is pertinent (or even necessary).

Rukhsana, I honestly don’t know how SR-IOV would compare to a MF device with VT-d. Anyone else care to chime in here with more information?

By: Robert

Robert — Fri, 31 Dec 2010 01:00:39 +0000

The Cisco UCS M81KR does NOT use SR-IOV. This was to allow Cisco to provide device drivers for new & older OSes without having to wait for the OS vendors to package/include them. The M81KR is SR-IOV capable with a firmware update so when the time comes, it can function under the standard SR-IOV or under Cisco-specific operation.

By: Anjali

Anjali — Wed, 21 Jul 2010 22:19:17 +0000

Scott,
I am interested in knowing whether the yukon-marvell chip 88E8022 supports SR-IOV or MR-IOV. ?
Also, how does the performance from SR-IOV compare with IOMMU?

By: Brian Johnson

Brian Johnson — Thu, 04 Feb 2010 01:07:28 +0000

Scott,

Just to let you know that we just released the 10Gb SR-IOV driver for Xen. Now both 1Gb and 10Gb Intel Adapters have SR-IOV support.

SourceForge also has ixgbe (base/PF) and ixgbevf (Linux VF) available for download:

http://sourceforge.net/projects/e1000/files/

By: rukhsana

rukhsana — Thu, 07 Jan 2010 09:39:25 +0000

Hi Scott,

Can you provide a comparison of how SR-IOV stacks up against MF cards used in conjunction with Vt-d.