similar to: [PATCH] virtio_ring: fix packed ring event may missing

On 2019/10/22 ??2:48, Liu, Yong wrote: > Hi Jason, > My answers are inline. > >> -----Original Message----- >> From: Jason Wang [mailto:jasowang at redhat.com] >> Sent: Tuesday, October 22, 2019 10:45 AM >> To: Liu, Yong <yong.liu at intel.com>; mst at redhat.com; Bie, Tiwei >> <tiwei.bie at intel.com> >> Cc: virtualization at

On Tue, Oct 22, 2019 at 01:10:04AM +0800, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was

On Tue, Oct 22, 2019 at 01:10:04AM +0800, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was

From: Marvin Liu <yong.liu at intel.com> When VIRTIO_F_RING_EVENT_IDX is negotiated, virtio devices can use virtqueue_enable_cb_delayed_packed to reduce the number of device interrupts. At the moment, this is the case for virtio-net when the napi_tx module parameter is set to false. In this case, the virtio driver selects an event offset and expects that the device will send a

On 2019/10/22 ??1:10, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was negotiated. So flags at

On Tue, Oct 22, 2019 at 01:10:04AM +0800, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was

On Wed, Jul 11, 2018 at 10:27:10AM +0800, Tiwei Bie wrote: > This commit introduces the EVENT_IDX support in packed ring. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> Besides the usual comment about hard-coded constants like <<15: does this actually do any good for performance? We don't have to if we do not want to. > --- > drivers/virtio/virtio_ring.c |

Hello everyone, This patch set implements packed ring support in virtio driver. Some functional tests have been done with Jason's packed ring implementation in vhost: https://lkml.org/lkml/2018/7/3/33 Both of ping and netperf worked as expected. v1 -> v2: - Use READ_ONCE() to read event off_wrap and flags together (Jason); - Add comments related to ccw (Jason); RFC (v6) -> v1: -

Hello everyone, This patch set implements packed ring support in virtio driver. Some functional tests have been done with Jason's packed ring implementation in vhost: https://lkml.org/lkml/2018/7/3/33 Both of ping and netperf worked as expected. v1 -> v2: - Use READ_ONCE() to read event off_wrap and flags together (Jason); - Add comments related to ccw (Jason); RFC (v6) -> v1: -

This commit introduces the EVENT_IDX support in packed ring. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 73 ++++++++++++++++++++++++++++++++---- 1 file changed, 65 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index cb833a82054b..4b3f9e1a3cab 100644 --- a/drivers/virtio/virtio_ring.c +++

This commit introduces the EVENT_IDX support in packed ring. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 73 ++++++++++++++++++++++++++++++++---- 1 file changed, 65 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index f317b485ba54..f79a1e17f7d1 100644 --- a/drivers/virtio/virtio_ring.c +++

On Wed, Jul 11, 2018 at 10:27:08AM +0800, Tiwei Bie wrote: > This commit introduces the support for creating packed ring. > All split ring specific functions are added _split suffix. > Some necessary stubs for packed ring are also added. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> I'd rather have a patch just renaming split functions, then add all packed stuff

On Wed, Jul 11, 2018 at 10:27:08AM +0800, Tiwei Bie wrote: > This commit introduces the support for creating packed ring. > All split ring specific functions are added _split suffix. > Some necessary stubs for packed ring are also added. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> I'd rather have a patch just renaming split functions, then add all packed stuff

Hello everyone, This patch set implements packed ring support in virtio driver. Some functional tests have been done with Jason's packed ring implementation in vhost: https://lkml.org/lkml/2018/7/3/33 Both of ping and netperf worked as expected. RFC (v6) -> v1: - Avoid extra virtio_wmb() in virtqueue_enable_cb_delayed_packed() when event idx is off (Jason); - Fix bufs calculation in

On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote: > On 2018?05?08? 14:44, Tiwei Bie wrote: > > On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote: > > > On 2018?05?08? 11:05, Jason Wang wrote: > > > > > Because in virtqueue_enable_cb_delayed(), we may set an > > > > > event_off which is bigger than new and both of them have >

On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote: > On 2018?05?08? 14:44, Tiwei Bie wrote: > > On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote: > > > On 2018?05?08? 11:05, Jason Wang wrote: > > > > > Because in virtqueue_enable_cb_delayed(), we may set an > > > > > event_off which is bigger than new and both of them have >

On Thu, Oct 11, 2018 at 08:12:21PM +0800, Tiwei Bie wrote: > > > But if it's not too late, I second for a OUT_OF_ORDER feature. > > > Starting from in order can have much simpler code in driver. > > > > > > Thanks > > > > It's tricky to change the flag polarity because of compatibility > > with legacy interfaces. Why is this such a

On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote: > On 2018?05?08? 11:05, Jason Wang wrote: > > > > > > Because in virtqueue_enable_cb_delayed(), we may set an > > > event_off which is bigger than new and both of them have > > > wrapped. And in this case, although new is smaller than > > > event_off (i.e. the third param -- old), new

On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote: > On 2018?05?08? 11:05, Jason Wang wrote: > > > > > > Because in virtqueue_enable_cb_delayed(), we may set an > > > event_off which is bigger than new and both of them have > > > wrapped. And in this case, although new is smaller than > > > event_off (i.e. the third param -- old), new

On Tue, May 08, 2018 at 05:34:40PM +0800, Jason Wang wrote: > On 2018?05?08? 17:16, Tiwei Bie wrote: > > On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote: > > > On 2018?05?08? 14:44, Tiwei Bie wrote: > > > > On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote: > > > > > On 2018?05?08? 11:05, Jason Wang wrote: > > > > >