On Thu, 2013-10-31 at 19:47 +0800, Jason Wang wrote: > Commit 2613af0ed18a11d5c566a81f9a6510b73180660a (virtio_net: migrate mergeable > rx buffers to page frag allocators) try to increase the payload/truesize for > MTU-sized traffic. But this will introduce the extra overhead for GSO packets > received because of the frag list. This commit tries to reduce this issue by > coalesce the possible rx frags when possible during rx. Test result shows the > about 15% improvement on full size GSO packet receiving (and even better than > commit 2613af0ed18a11d5c566a81f9a6510b73180660a). > > Before this commit: > ./netperf -H 192.168.100.4 > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4 > () port 0 AF_INET : demo > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 20303.87 > > After this commit: > ./netperf -H 192.168.100.4 > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4 () port 0 AF_INET : demo > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 23841.26 > > Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> > Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> > Cc: Michael Dalton <mwdalton@xxxxxxxxxx> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> > --- Excellent ! We now have 2 or 3 frags per skb, like tcp stack manages to do on output path. Michael Dalton is also working on a autotuning patch, using an EWMA, so that the size of individual sg blocks can vary from 1500 to 4096, this might show even better throughput, we'll see. Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx> _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
