On Wed, Mar 16, 2011 at 05:09:55PM -0700, Shirley Ma wrote: > This patch addresses small message size performance in a situation the > KVM guest virtio_net TX queue overrun. This patch adds a new API in > virtio_ring for ring capacity check; and remove KVM guest virtio_net TX > queue send completion interrupts completely. The test has shown that > whenever the queue is overrun, it's much better to drop a few packets > than stopping TX queue and waiting for host to notify the guest to wake > up the TX queue again, the small messages size performance gain for > single TCP_STREAM BW could be up to 200%-300% and better than bare > metal, and no regression has been found in other situation. > > Performance data for 10GbE, > > KVM guest to local host: > ------------------------ > Message size 2.6.38-rc8 2.6.38-rc8+patch > 1024 1770.61 4528.37 > 2048 2702.30 7110.95 > 4096 5256.84 10104.76 > 8192 7543.66 10945.93 > 16K 10500.47 10783.50 > 64K 13718.62 13640.80 > > KVM guest to remote host: > -------------------------- > Message size Bare Metal 2.6.38-rc8 2.6.38-rc8+patch > 1024 1802.67 2381.41 5599.15 > 2048 4317.87 4094.12 9241.86 > 4096 6266.15 5231.24 9321.87 > 8192 8409.17 7952.74 9265.45 > 16K 9351.63 8260.68 8310.29 > 64K 9347.94 9103.75 9094.38 > > Thanks > Shirley Could you add CPU utilization data pls? I also wonder what does this do to UDP? Won't a lot of packets be dropped? -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
