[Virtio-fs] xfstest results for virtio-fs on aarch64

[Stefan Hajnoczi]

On Fri, Oct 11, 2019 at 04:36:47PM -0400, Vivek Goyal wrote:
> On Sat, Oct 12, 2019 at 05:13:51AM +0900, Chirantan Ekbote wrote:
> > On Sat, Oct 12, 2019 at 4:59 AM Vivek Goyal <vgoyal at redhat.com> wrote:
> > @@ -922,7 +990,8 @@ static int virtio_fs_enqueue_req(struct virtqueue
> > *vq, struct fuse_req *req)
> >  static void virtio_fs_wake_pending_and_unlock(struct fuse_iqueue *fiq)
> >  __releases(fiq->waitq.lock)
> >  {
> > -       unsigned queue_id = VQ_REQUEST; /* TODO multiqueue */
> > +       /* unsigned queue_id = VQ_REQUEST; /\* TODO multiqueue *\/ */
> > +       unsigned queue_id;
> >         struct virtio_fs *fs;
> >         struct fuse_conn *fc;
> >         struct fuse_req *req;
> > @@ -937,6 +1006,7 @@ __releases(fiq->waitq.lock)
> >         spin_unlock(&fiq->waitq.lock);
> > 
> >         fs = fiq->priv;
> > +       queue_id = (req->in.h.unique % (fs->nvqs - 1)) + 1;
> >         fc = fs->vqs[queue_id].fud->fc;
> > 
> >         dev_dbg(&fs->vqs[queue_id].vq->vdev->dev,
> > 
> > 
> > This is simply round-robin scheduling but even going from one to two
> > queues gives a significant performance improvement (especially because
> > crosvm doesn't support shared memory regions yet).
> 
> Interesting. I thought virtiofsd is hard coded right now to support
> only one queue. Did you modify virtiofsd to support more than one
> request queue?

Right, virtiofsd currently refuses to bring up more than 1 request
queue.  The code can actually handle multiqueue now but there is no
command-line support for it yet.  The ability to set CPU affinity for
virtqueue threads could be introduced at the same time as enabling
multiqueue.

Stefan
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