On Wed, Jul 29, 2009 at 03:26:37PM -0700, Robert Bays wrote:
> On 7/29/09 11:57 AM, Alexis Rosen wrote:
> > On Jul 29, 2009, at 5:17 AM, sthaug@xxxxxxxxxx wrote:
> >>> I was wondering if anyone is running Quagga on Xen? What is
> >>> throughput/latency like?
> >> This is a function of kernel forwarding performance. Quagga doesn't
> >> do forwarding.
> At my company, we have done extensive testing of the forwarding
> performance of Linux vms on Xen. We use Quagga as our routing suite,
> but as previously mentioned it has nothing to do with forwarding
> performance. I removed the Quagga list from this thread to stop the
> cross post.
> For testing we follow rfc2544. To give you some representative numbers,
> we see anywhere between 100-150mbps zero loss throughput for
> bi-directional 64byte packet streams on a 3.0ghz Intel quad core
> processor. This follows the typical bandwidth curve up to roughly
> 1.6gig for large packet sizes. We are currently running a Linux 2.6.30
> pv_ops enabled kernel in the domU. We have noticed that if we share a
> physical processor core with more than one vm we will take a roughly 2%
> hit to overall performance. Interestingly, a third or fourth vm on the
> same core still only incurs the same 2% penalty. Throughput is highly
> dependent on the system; i.e. processor model, motherboard chipsets, bus
> type and location of the card on the bus, etc... Throughput also has a
> fairly high jitter factor. The system can be tuned to mitigate the
> jitter, but at a loss of overall throughput and an average increase in
Interesting. Did you profile what limits the performance, or uses the cpu?
Bridging in dom0? Xen?
Are you familiar with the netchannel2 development stuff?
> If the system is configured for PCI pass through, expect a much higher
> throughput. It's more on the order of 650mbps zero-loss for
> bi-directional streams of small packet sizes. HVM domUs aren't even
> worth using for networking.
Yeah, PV guests are much easier, faster and stable for this purpose.
(and yeah I know you can use PV-on-HVM drivers on HVM domain).
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