Hi Clay..... On Wed, Jun 15, 2011 at 05:32, Clay Andreasen <c...@cray.com> wrote: > I have a network device simulation that I am connecting to multiple > instances of Qemu (nodes) via a shared memory queue. It works pretty well > as > long as all of the nodes are initiating communication but when one node is > passive, it must poll to get packets. So far the fastest I have been able > to > get it to poll is about every 2M emulated clocks.
that means, once every ... 1 mili second? (I doubt it, but theoritically possible) > This is with CONFIG_HIGH_RES_TIMERS and CONFIG_NO_HZ on the host. > I also set MIN_TIMER_REARM_NS in qemu-timer.c to 100000. > Is there some way to increase the polling rate by about an order of > magnitude? with the way current kernel did fair scheduling, your problem is timing handling latency actually i.e timer is fast, but the handler needs some time to catch up. what I can suggest is experimenting with rt- kernel and put yourself into such high priority process with realtime scheduling, keep reducing MIN_TIMER_REARM_NS.. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
