similar to: [PATCH 1/2] virtio: fix typos of memory barriers

This change makes it so that instead of using smp_wmb/rmb which varies depending on the kernel configuration we can can use dma_wmb/rmb which for most architectures should be equal to or slightly more strict than smp_wmb/rmb. The advantage to this is that these barriers are available to uniprocessor builds as well so the performance should improve under such a configuration. Signed-off-by:

This change makes it so that instead of using smp_wmb/rmb which varies depending on the kernel configuration we can can use dma_wmb/rmb which for most architectures should be equal to or slightly more strict than smp_wmb/rmb. The advantage to this is that these barriers are available to uniprocessor builds as well so the performance should improve under such a configuration. Signed-off-by:

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 |

On 2018?04?25? 13:15, Tiwei Bie wrote: > This commit introduces the event idx support in packed > ring. This feature is temporarily disabled, because the > implementation in this patch may not work as expected, > and some further discussions on the implementation are > needed, e.g. do we have to check the wrap counter when > checking whether a kick is needed? > >

On 2018?04?25? 13:15, Tiwei Bie wrote: > This commit introduces the event idx support in packed > ring. This feature is temporarily disabled, because the > implementation in this patch may not work as expected, > and some further discussions on the implementation are > needed, e.g. do we have to check the wrap counter when > checking whether a kick is needed? > >

On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > This commit introduces the event idx support in packed > > > ring. This feature is temporarily disabled, because the > > > implementation in this patch may not work as expected, > > >

On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > This commit introduces the event idx support in packed > > > ring. This feature is temporarily disabled, because the > > > implementation in this patch may not work as expected, > > >

On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > > > This commit introduces the event idx

On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > > > This commit introduces the event idx

Getting use of virtio rings correct is tricky, and a recent patch saw an implementation of in-kernel rings (as separate from userspace). This patch attempts to abstract the business of dealing with the virtio ring layout from the access (userspace or direct); to do this, we use function pointers, which gcc inlines correctly. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> ---

Getting use of virtio rings correct is tricky, and a recent patch saw an implementation of in-kernel rings (as separate from userspace). This patch attempts to abstract the business of dealing with the virtio ring layout from the access (userspace or direct); to do this, we use function pointers, which gcc inlines correctly. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> ---

virtio is using barriers to order memory accesses, thus dma_wmb/rmb is a good match. Build-tested on x86: Before [mst at tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o After mst at tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename

virtio is using barriers to order memory accesses, thus dma_wmb/rmb is a good match. Build-tested on x86: Before [mst at tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o After mst at tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename

Hello everyone, This RFC implements packed ring support in virtio driver. Some simple functional tests have been done with Jason's packed ring implementation in vhost: https://lkml.org/lkml/2018/4/23/12 Both of ping and netperf worked as expected (with EVENT_IDX disabled). But there are below known issues: 1. Reloading the guest driver will break the Tx/Rx; 2. Zeroing the flags when

Hello everyone, This RFC implements packed ring support in virtio driver. Some simple functional tests have been done with Jason's packed ring implementation in vhost: https://lkml.org/lkml/2018/4/23/12 Both of ping and netperf worked as expected (with EVENT_IDX disabled). TODO: - Refinements (for code and commit log); - More tests; - Bug fixes; RFC v3 -> RFC v4: - Make ID allocation

Hello everyone, This RFC implements packed ring support in virtio driver. Some functional tests have been done with Jason's packed ring implementation in vhost (RFC v5): https://lwn.net/Articles/755862/ Both of ping and netperf worked as expected. TODO: - Refinements (for code and commit log); - More tests and bug fixes if any; - Send the formal patch set; RFC v5 -> RFC v6: - Avoid

On Thu, May 03, 2018 at 09:11:16AM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 06:42:57PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > > > On Wed, May

On Thu, May 03, 2018 at 09:11:16AM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 06:42:57PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > > > On Wed, May

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: -