On Wed, Oct 05 2011, Christoph Hellwig wrote: > Add an alternate I/O path that implements ->make_request for virtio-blk. > This is required for high IOPs devices which get slowed down to 1/5th of > the native speed by all the locking, memory allocation and other overhead > in the request based I/O path. We definitely have some performance fruit hanging rather low in that path, but a factor 5 performance difference sounds insanely excessive. I haven't looked at virtio_blk in detail, but I've done 500K+ IOPS on request based drivers before (yes, on real hardware). So it could be that virtio_blk is just doing things rather suboptimally in some places, and that it would be possible to claim most of that speedup there too. -- Jens Axboe -- 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
