Il 09/10/2012 11:26, Avi Kivity ha scritto: > On 10/09/2012 11:08 AM, Stefan Hajnoczi wrote: >> Here are the steps that have been mentioned: >> >> 1. aio fastpath - for raw-posix and other aio block drivers, can we reduce >> I/O >> request latency by skipping block layer coroutines? > > Is coroutine overhead noticable?
I'm thinking more about throughput than latency. If the iothread becomes CPU-bound, then everything is noticeable. >> I'm also curious about virtqueue_pop()/virtqueue_push() outside the QEMU >> mutex >> although that might be blocked by the current work around MMIO/PIO dispatch >> outside the global mutex. > > It is, yes. It should only require unlocked memory map/unmap, not MMIO dispatch. The MMIO/PIO bits are taken care of by ioeventfd. Paolo
