On 09/02/2013 02:30 PM, Jason Wang wrote: > On 09/02/2013 01:56 PM, Michael S. Tsirkin wrote: >> > On Fri, Aug 30, 2013 at 12:29:22PM +0800, Jason Wang wrote: >>> >> As Michael point out, We used to limit the max pending DMAs to get better cache >>> >> utilization. But it was not done correctly since it was one done when there's no >>> >> new buffers submitted from guest. Guest can easily exceeds the limitation by >>> >> keeping sending packets. >>> >> >>> >> So this patch moves the check into main loop. Tests shows about 5%-10% >>> >> improvement on per cpu throughput for guest tx. But a 5% drop on per cpu >>> >> transaction rate for a single session TCP_RR. >> > Any explanation for the drop? single session TCP_RR is unlikely to >> > exceed VHOST_MAX_PEND, correct? > Unlikely to exceed. Recheck the result, looks like it was not stable > enough. Will re-test and report. Re-tested with more iterations, result shows no difference on TCP_RR test and 5%-10% improvement on per cpu throughput for guest tx. Will post V3 soon. -- 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
