similar to: [PATCH net] vhost_net: correctly check tx avail during rx busy polling

We check tx avail through vhost_enable_notify() in the past which is wrong since it only checks whether or not guest has filled more available buffer since last avail idx synchronization which was just done by vhost_vq_avail_empty() before. What we really want is checking pending buffers in the avail ring. Fix this by calling vhost_vq_avail_empty() instead. This issue could be noticed by doing

We check tx avail through vhost_enable_notify() in the past which is wrong since it only checks whether or not guest has filled more available buffer since last avail idx synchronization which was just done by vhost_vq_avail_empty() before. What we really want is checking pending buffers in the avail ring. Fix this by calling vhost_vq_avail_empty() instead. This issue could be noticed by doing

On Fri, Sep 01, 2017 at 05:02:50PM +0800, Jason Wang wrote: > We check tx avail through vhost_enable_notify() in the past which is > wrong since it only checks whether or not guest has filled more > available buffer since last avail idx synchronization which was just > done by vhost_vq_avail_empty() before. What we really want is checking > pending buffers in the avail ring. These

This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected mlx4 - Guest

This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected mlx4 - Guest

From: Tonghao Zhang <xiangxia.m.yue at gmail.com> This patches improve the guest receive and transmit performance. On the handle_tx side, we poll the sock receive queue at the same time. handle_rx do that in the same way. This patches are splited from previous big patch: http://patchwork.ozlabs.org/patch/934673/ For more performance report, see patch 4. Tonghao Zhang (4): net: vhost:

From: Tonghao Zhang <xiangxia.m.yue at gmail.com> This patches improve the guest receive and transmit performance. On the handle_tx side, we poll the sock receive queue at the same time. handle_rx do that in the same way. For more performance report, see patch 4. v3 -> v4: fix some issues v2 -> v3: This patches are splited from previous big patch:

This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected mlx4 - Guest

This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected mlx4 - Guest

From: Tonghao Zhang <xiangxia.m.yue at gmail.com> This patches improve the guest receive and transmit performance. On the handle_tx side, we poll the sock receive queue at the same time. handle_rx do that in the same way. For more performance report, see patch 4. v4 -> v5: fix some issues v3 -> v4: fix some issues v2 -> v3: This patches are splited from previous big patch:

From: Tonghao Zhang <xiangxia.m.yue at gmail.com> This patches improve the guest receive and transmit performance. On the handle_tx side, we poll the sock receive queue at the same time. handle_rx do that in the same way. For more performance report, see patch 4. v4 -> v5: fix some issues v3 -> v4: fix some issues v2 -> v3: This patches are splited from previous big patch:

Under heavy load vhost tx busypoll tend not to suppress vq kicks, which causes poor guest tx performance. The detailed scenario is described in commitlog of patch 2. Rx seems not to have that serious problem, but for consistency I made a similar change on rx to avoid rx wakeups (patch 3). Additionary patch 4 is to avoid rx kicks under heavy load during busypoll. Tx performance is greatly improved

On 2018/07/04 13:31, xiangxia.m.yue at gmail.com wrote: ... > +static void vhost_net_busy_poll(struct vhost_net *net, > + struct vhost_virtqueue *rvq, > + struct vhost_virtqueue *tvq, > + bool rx) > +{ > + unsigned long uninitialized_var(endtime); > + unsigned long busyloop_timeout; > + struct socket *sock; > + struct vhost_virtqueue *vq = rx ? tvq : rvq; > +

On 2018/07/04 13:31, xiangxia.m.yue at gmail.com wrote: ... > +static void vhost_net_busy_poll(struct vhost_net *net, > + struct vhost_virtqueue *rvq, > + struct vhost_virtqueue *tvq, > + bool rx) > +{ > + unsigned long uninitialized_var(endtime); > + unsigned long busyloop_timeout; > + struct socket *sock; > + struct vhost_virtqueue *vq = rx ? tvq : rvq; > +

Under heavy load vhost busypoll may run without suppressing notification. For example tx zerocopy callback can push tx work while handle_tx() is running, then busyloop exits due to vhost_has_work() condition and enables notification but immediately reenters handle_tx() because the pushed work was tx. In this case handle_tx() tries to disable notification again, but when using event_idx it by

Under heavy load vhost busypoll may run without suppressing notification. For example tx zerocopy callback can push tx work while handle_tx() is running, then busyloop exits due to vhost_has_work() condition and enables notification but immediately reenters handle_tx() because the pushed work was tx. In this case handle_tx() tries to disable notification again, but when using event_idx it by

On 2018?07?02? 20:57, xiangxia.m.yue at gmail.com wrote: > From: Tonghao Zhang <xiangxia.m.yue at gmail.com> > > Factor out generic busy polling logic and will be > used for in tx path in the next patch. And with the patch, > qemu can set differently the busyloop_timeout for rx queue. > > Signed-off-by: Tonghao Zhang <zhangtonghao at didichuxing.com> > --- >

On 2018?07?02? 20:57, xiangxia.m.yue at gmail.com wrote: > From: Tonghao Zhang <xiangxia.m.yue at gmail.com> > > Factor out generic busy polling logic and will be > used for in tx path in the next patch. And with the patch, > qemu can set differently the busyloop_timeout for rx queue. > > Signed-off-by: Tonghao Zhang <zhangtonghao at didichuxing.com> > --- >

Hi all: This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected

Hi all: This series tries to add basic busy polling for vhost net. The idea is simple: at the end of tx/rx processing, busy polling for new tx added descriptor and rx receive socket for a while. The maximum number of time (in us) could be spent on busy polling was specified ioctl. Test A were done through: - 50 us as busy loop timeout - Netperf 2.6 - Two machines with back to back connected