On Thu, Nov 07, 2019 at 01:39:28PM +0100, Eelco Chaudron wrote: > > > On 7 Nov 2019, at 12:36, Ilya Maximets wrote: > > >Until now there was only two options for XDP mode in OVS: SKB or DRV. > >i.e. 'generic XDP' or 'native XDP with zero-copy enabled'. > > > >Devices like 'veth' interfaces in Linux supports native XDP, but > >doesn't support zero-copy mode. This case can not be covered by > >existing API and we have to use slower generic XDP for such devices. > >There are few more issues, e.g. TCP is not supported in generic XDP > >mode for veth interfaces due to kernel limitations, however it is > >supported in native mode. > > > >This change introduces ability to use native XDP without zero-copy > >along with best-effort configuration option that enabled by default. > >In best-effort case OVS will sequentially try different modes starting > >from the fastest one and will choose the first acceptable for current > >interface. This will guarantee the best possible performance. > > > >If user will want to choose specific mode, it's still possible by > >setting the 'options:xdp-mode'. > > > >This change additionally changes the API by renaming the configuration > >knob from 'xdpmode' to 'xdp-mode' and also renaming the modes > >themselves to be more user-friendly. > > > >The full list of currently supported modes: > > * native-with-zerocopy - former DRV > > * native - new one, DRV without zero-copy > > * generic - former SKB > > * best-effort - new one, chooses the best available from > > 3 above modes > > > >Since 'best-effort' is a default mode, users will not need to > >explicitely set 'xdp-mode' in most cases. > > > >TCP related tests enabled back in system afxdp testsuite, because > >'best-effort' will choose 'native' mode for veth interfaces > >and this mode has no issues with TCP. > > > >Signed-off-by: Ilya Maximets <i.maxim...@ovn.org> > > No review, I was running some performance tests for the OVS conference > presentation so quickly tried this patch (assuming performance would > increase :)… > > So with the native option (default for tap) I see a decrease, :(, in > performance over the skb mode (this is with my usual ovs_perf PVP test > setup). > > With the patch applied, and default configuration > (xdp-mode-in-use=native-with-zerocopy for my tap): > > "Physical to Virtual to Physical test, L3 flows[port redirect]" > , Packet size > Number of flows, 64 > 1, 711581 > 100, 673152 > 1000, 617733 > > Here you will even see a performance drop with multiple IP flows (this is a > single queue config). > > With SKB mode (xdp-mode-in-use=generic): > > "Physical to Virtual to Physical test, L3 flows[port redirect]" > , Packet size > Number of flows, 64 > 1, 800796 > 100, 800912 > 1000, 800133 >
Hi Eelco, I have another question (not directly related to this patch). When doing PVP testing, what's the total CPU consumption? I'm trying to think about the efficiency, ex: Packet forwarding rate / CPU utilization For native-with-zerocopy, is it correct that your system uses ksoftirqd/x 100% (rx port) ksoftirqd/y 100% (tx port) qemu-kvm 100% vhost_net 100% ovs-vswitchd 100% (pmd thead) Or with need_wakeup, it's lower than this number? Thanks William _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
