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 > etc.. > > 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. https://perf.wiki.kernel.org/index.php/Tutorial Regards, - Greg > > Best Regards > avi > > > -----Original Message----- > > From: Bodireddy, Bhanuprakash [mailto:[email protected]] > > Sent: Wednesday, 24 May, 2017 3:43 PM > > To: Avi Cohen (A); [email protected] > > 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. > > _______________________________________________ > discuss mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss _______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
