On Tue, Mar 1, 2022 at 1:15 AM Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 28 Feb 2022 15:46:56 +0800 > Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > On Mon, Feb 28, 2022 at 11:38 AM Harold Huang <baymaxhuang@xxxxxxxxx> wrote: > > > > > > In tun, NAPI is supported and we can also use NAPI in the path of > > > batched XDP buffs to accelerate packet processing. What is more, after > > > we use NAPI, GRO is also supported. The iperf shows that the throughput of > > > single stream could be improved from 4.5Gbps to 9.2Gbps. Additionally, 9.2 > > > Gbps nearly reachs the line speed of the phy nic and there is still about > > > 15% idle cpu core remaining on the vhost thread. > > > > > > Test topology: > > > [iperf server]<--->tap<--->dpdk testpmd<--->phy nic<--->[iperf client] > > > > > > Iperf stream: > > > iperf3 -c 10.0.0.2 -i 1 -t 10 > > > > > > Before: > > > ... > > > [ 5] 5.00-6.00 sec 558 MBytes 4.68 Gbits/sec 0 1.50 MBytes > > > [ 5] 6.00-7.00 sec 556 MBytes 4.67 Gbits/sec 1 1.35 MBytes > > > [ 5] 7.00-8.00 sec 556 MBytes 4.67 Gbits/sec 2 1.18 MBytes > > > [ 5] 8.00-9.00 sec 559 MBytes 4.69 Gbits/sec 0 1.48 MBytes > > > [ 5] 9.00-10.00 sec 556 MBytes 4.67 Gbits/sec 1 1.33 MBytes > > > - - - - - - - - - - - - - - - - - - - - - - - - - > > > [ ID] Interval Transfer Bitrate Retr > > > [ 5] 0.00-10.00 sec 5.39 GBytes 4.63 Gbits/sec 72 sender > > > [ 5] 0.00-10.04 sec 5.39 GBytes 4.61 Gbits/sec receiver > > > > > > After: > > > ... > > > [ 5] 5.00-6.00 sec 1.07 GBytes 9.19 Gbits/sec 0 1.55 MBytes > > > [ 5] 6.00-7.00 sec 1.08 GBytes 9.30 Gbits/sec 0 1.63 MBytes > > > [ 5] 7.00-8.00 sec 1.08 GBytes 9.25 Gbits/sec 0 1.72 MBytes > > > [ 5] 8.00-9.00 sec 1.08 GBytes 9.25 Gbits/sec 77 1.31 MBytes > > > [ 5] 9.00-10.00 sec 1.08 GBytes 9.24 Gbits/sec 0 1.48 MBytes > > > - - - - - - - - - - - - - - - - - - - - - - - - - > > > [ ID] Interval Transfer Bitrate Retr > > > [ 5] 0.00-10.00 sec 10.8 GBytes 9.28 Gbits/sec 166 sender > > > [ 5] 0.00-10.04 sec 10.8 GBytes 9.24 Gbits/sec receiver > > > > > > Reported-at: https://lore.kernel.org/all/CACGkMEvTLG0Ayg+TtbN4q4pPW-ycgCCs3sC3-TF8cuRTf7Pp1A@xxxxxxxxxxxxxx > > > Signed-off-by: Harold Huang <baymaxhuang@xxxxxxxxx> > > > > Acked-by: Jason Wang <jasowang@xxxxxxxxxx> > > Would this help when using sendmmsg and recvmmsg on the TAP device? > Asking because interested in speeding up another use of TAP device, and wondering > if this would help. As Jason said, sendmmsg()/recvmsg() could not be used on tuntap. But I think another choice is to use writev/readv directly on the ttunap fd, which will call tun_get_user to send msg and NAPI has also been supported.
