Am 28.11.2014 um 18:31 hat Paolo Bonzini geschrieben: > > > On 28/11/2014 17:40, Kevin Wolf wrote: > >> > I still believe we will end with some kind of coroutine bypass scheme > >> > (even coroutines _do_ allocate an AIOCB, so calling bdrv_aio_readv > >> > directly can help), but hey it cannot hurt to optimize hot code. > > > > Not sure if speculations about the future belong into commit messages, > > but while it may turn out that a bypass is required in the end (I hope > > it doesn't), the part about AIOCBs is wrong if you really consistently > > use coroutines all the way down from the device to the block driver. > > This is much harder for virtio-scsi than for virtio-blk, though.
Why is that? At least replacing the bdrv_aio_*() call by coroutine_create/coroutine_enter/bdrv_co_*() is a mechanical change that shouldn't be any harder for virtio-scsi. Whether we can optimise even more by integration the device more with coroutines might be a different problem, but at this point you've already got rid of AIOCBs. Kevin
