On Wed, Jun 06, 2012 at 04:25:55PM +0100, Stefan Hajnoczi wrote:
On Mon, Jun 4, 2012 at 12:11 PM, Michael S. Tsirkin m...@redhat.com wrote:
On Fri, Jun 01, 2012 at 10:13:06AM +0100, Stefan Hajnoczi wrote:
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index
On Mon, Jun 4, 2012 at 12:15 PM, Michael S. Tsirkin m...@redhat.com wrote:
On Fri, Jun 01, 2012 at 10:13:06AM +0100, Stefan Hajnoczi wrote:
Other block drivers (cciss, rbd, nbd) use spin_unlock_irq() so I followed
that.
To me this seems wrong: blk_run_queue() uses spin_lock_irqsave() but we
On Mon, Jun 4, 2012 at 12:11 PM, Michael S. Tsirkin m...@redhat.com wrote:
On Fri, Jun 01, 2012 at 10:13:06AM +0100, Stefan Hajnoczi wrote:
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 774c31d..d674977 100644
--- a/drivers/block/virtio_blk.c
+++
On 06/01/2012 05:13 PM, Stefan Hajnoczi wrote:
Holding the vblk-lock across kick causes poor scalability in SMP
guests. If one CPU is doing virtqueue kick and another CPU touches the
vblk-lock it will have to spin until virtqueue kick completes.
This patch reduces system% CPU utilization in
On Fri, Jun 01, 2012 at 10:13:06AM +0100, Stefan Hajnoczi wrote:
Holding the vblk-lock across kick causes poor scalability in SMP
guests. If one CPU is doing virtqueue kick and another CPU touches the
vblk-lock it will have to spin until virtqueue kick completes.
This patch reduces system%
On Fri, Jun 01, 2012 at 10:13:06AM +0100, Stefan Hajnoczi wrote:
Other block drivers (cciss, rbd, nbd) use spin_unlock_irq() so I followed
that.
To me this seems wrong: blk_run_queue() uses spin_lock_irqsave() but we enable
irqs with spin_unlock_irq(). If the caller of blk_run_queue() had
Holding the vblk-lock across kick causes poor scalability in SMP
guests. If one CPU is doing virtqueue kick and another CPU touches the
vblk-lock it will have to spin until virtqueue kick completes.
This patch reduces system% CPU utilization in SMP guests that are
running multithreaded I/O-bound
