[ovs-discuss] OVS vs OVS-DPDK
gvrose8192 at gmail.com
Wed May 24 19:23:40 UTC 2017
On Wed, 2017-05-24 at 12:52 +0000, Avi Cohen (A) wrote:
> Thanks you Bhanuprakash for your reply.
> I indeed use vhost-user interface for OVS-DPDK and vhost-net for standard OVS.
> Also saw this article in the link you've sent.
> But still try to find out the reasons for the boost performance with OVS-DPDK (note that VMs on both setup are unaware to OVS/OVS-DPDK which is running in the host)
> Also I found out that the bottleneck are the VMs and not the vswitch running in the host.
> These reasons for poor performance can be for example:
> 1. number of packet copies in the path NIC - OVS - OS-guest-virtio - Application on guest
> 2. interrupt upon receiving a packet
> 3. # of context-switch / VM-exit
> I didn't see any info regarding these potential reasons on the docs.
Have you ever tried using perf? It could help you identify performance
bottlenecks if that's what you're researching.
> Best Regards
> > -----Original Message-----
> > From: Bodireddy, Bhanuprakash [mailto:bhanuprakash.bodireddy at intel.com]
> > Sent: Wednesday, 24 May, 2017 3:43 PM
> > To: Avi Cohen (A); ovs-discuss at openvswitch.org
> > Subject: RE: OVS vs OVS-DPDK
> > >Question: what are the additional overhead in the standard OVS that cause
> > >to poor performance related to the OVS-DPDK setup ?
> > >I'm not talking about the PMD improvements (OVS-DPDK) running on the
> > >host - but on overhead in the VM context in the standard OVS setup
> > When running guest instances on OvS, vhost-net driver modules shall be used.
> > In case of OvS-DPDK, vhost-user library is used and runs entirely in user space
> > and is the reason for higher performance in VM context Refer to this document
> > on some internals of vhost-library:
> > http://dpdk.readthedocs.io/en/v16.07/sample_app_ug/vhost.html
> > - Bhanuprakash.
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> discuss at openvswitch.org
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