On Sun, Aug 09, 2009 at 01:01:35PM +0300, Avi Kivity wrote: > On 08/06/2009 07:35 PM, Christoph Hellwig wrote: >> Michael suggested to me a while ago to try MSI with virtio-blk and I >> played with this small patch: >> >> >> Index: qemu-kvm/hw/virtio-blk.c >> =================================================================== >> --- qemu-kvm.orig/hw/virtio-blk.c >> +++ qemu-kvm/hw/virtio-blk.c >> @@ -416,6 +416,7 @@ VirtIODevice *virtio_blk_init(DeviceStat >> s->vdev.get_config = virtio_blk_update_config; >> s->vdev.get_features = virtio_blk_get_features; >> s->vdev.reset = virtio_blk_reset; >> + s->vdev.nvectors = 2; some whitespace damage btw >> s->bs = bs; >> s->rq = NULL; >> if (strlen(ps = (char *)drive_get_serial(bs))) >> >> which gave about 5% speedups on 4k sized reads and writes, see the full >> iozone output I attached. Now getting the information about using >> multiple MSI vectors from the command line to virtio-blk similar to how >> virtio-net does seems extremly messy right now. Waiting for Gerd's >> additional qdev patches to make it easier as a qdev property. >> >> > > Looks good. Anthony, I think this applies upstream? This applies upstream, but we also need the flag to change # of vectors: for loading old images, but also for troubleshooting. Thus the qdev dependency. -- MST -- 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
