| Message ID | 1448435489-5949-4-git-send-email-jasowang@redhat.com |
|---|---|
| State | Awaiting Upstream, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: > This patch tries to poll for new added tx buffer or socket receive > queue for a while at the end of tx/rx processing. The maximum time > spent on polling were specified through a new kind of vring ioctl. > > Signed-off-by: Jason Wang <jasowang@redhat.com> One further enhancement would be to actually poll the underlying device. This should be reasonably straight-forward with macvtap (especially in the passthrough mode). > --- > drivers/vhost/net.c | 72 ++++++++++++++++++++++++++++++++++++++++++---- > drivers/vhost/vhost.c | 15 ++++++++++ > drivers/vhost/vhost.h | 1 + > include/uapi/linux/vhost.h | 11 +++++++ > 4 files changed, 94 insertions(+), 5 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 9eda69e..ce6da77 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -287,6 +287,41 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) > rcu_read_unlock_bh(); > } > > +static inline unsigned long busy_clock(void) > +{ > + return local_clock() >> 10; > +} > + > +static bool vhost_can_busy_poll(struct vhost_dev *dev, > + unsigned long endtime) > +{ > + return likely(!need_resched()) && > + likely(!time_after(busy_clock(), endtime)) && > + likely(!signal_pending(current)) && > + !vhost_has_work(dev) && > + single_task_running(); > +} > + > +static int vhost_net_tx_get_vq_desc(struct vhost_net *net, > + struct vhost_virtqueue *vq, > + struct iovec iov[], unsigned int iov_size, > + unsigned int *out_num, unsigned int *in_num) > +{ > + unsigned long uninitialized_var(endtime); > + > + if (vq->busyloop_timeout) { > + preempt_disable(); > + endtime = busy_clock() + vq->busyloop_timeout; > + while (vhost_can_busy_poll(vq->dev, endtime) && > + !vhost_vq_more_avail(vq->dev, vq)) > + cpu_relax(); > + preempt_enable(); > + } > + > + return vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), > + out_num, in_num, NULL, NULL); > +} > + > /* Expects to be always run from workqueue - which acts as > * read-size critical section for our kind of RCU. */ > static void handle_tx(struct vhost_net *net) > @@ -331,10 +366,9 @@ static void handle_tx(struct vhost_net *net) > % UIO_MAXIOV == nvq->done_idx)) > break; > > - head = vhost_get_vq_desc(vq, vq->iov, > - ARRAY_SIZE(vq->iov), > - &out, &in, > - NULL, NULL); > + head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, > + ARRAY_SIZE(vq->iov), > + &out, &in); > /* On error, stop handling until the next kick. */ > if (unlikely(head < 0)) > break; > @@ -435,6 +469,34 @@ static int peek_head_len(struct sock *sk) > return len; > } > > +static int vhost_net_peek_head_len(struct vhost_net *net, struct sock *sk) > +{ > + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; > + struct vhost_virtqueue *vq = &nvq->vq; > + unsigned long uninitialized_var(endtime); > + > + if (vq->busyloop_timeout) { > + mutex_lock(&vq->mutex); > + vhost_disable_notify(&net->dev, vq); > + > + preempt_disable(); > + endtime = busy_clock() + vq->busyloop_timeout; > + > + while (vhost_can_busy_poll(&net->dev, endtime) && > + skb_queue_empty(&sk->sk_receive_queue) && > + !vhost_vq_more_avail(&net->dev, vq)) > + cpu_relax(); > + > + preempt_enable(); > + > + if (vhost_enable_notify(&net->dev, vq)) > + vhost_poll_queue(&vq->poll); > + mutex_unlock(&vq->mutex); > + } > + > + return peek_head_len(sk); > +} > + > /* This is a multi-buffer version of vhost_get_desc, that works if > * vq has read descriptors only. > * @vq - the relevant virtqueue > @@ -553,7 +615,7 @@ static void handle_rx(struct vhost_net *net) > vq->log : NULL; > mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); > > - while ((sock_len = peek_head_len(sock->sk))) { > + while ((sock_len = vhost_net_peek_head_len(net, sock->sk))) { > sock_len += sock_hlen; > vhost_len = sock_len + vhost_hlen; > headcount = get_rx_bufs(vq, vq->heads, vhost_len, > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index b86c5aa..857af6c 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -285,6 +285,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, > vq->memory = NULL; > vq->is_le = virtio_legacy_is_little_endian(); > vhost_vq_reset_user_be(vq); > + vq->busyloop_timeout = 0; > } > > static int vhost_worker(void *data) > @@ -747,6 +748,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) > struct vhost_vring_state s; > struct vhost_vring_file f; > struct vhost_vring_addr a; > + struct vhost_vring_busyloop_timeout t; > u32 idx; > long r; > > @@ -919,6 +921,19 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) > case VHOST_GET_VRING_ENDIAN: > r = vhost_get_vring_endian(vq, idx, argp); > break; > + case VHOST_SET_VRING_BUSYLOOP_TIMEOUT: > + if (copy_from_user(&t, argp, sizeof(t))) { > + r = -EFAULT; > + break; > + } > + vq->busyloop_timeout = t.timeout; > + break; > + case VHOST_GET_VRING_BUSYLOOP_TIMEOUT: > + t.index = idx; > + t.timeout = vq->busyloop_timeout; > + if (copy_to_user(argp, &t, sizeof(t))) > + r = -EFAULT; > + break; > default: > r = -ENOIOCTLCMD; > } > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > index 2f3c57c..4b7d4fa 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -115,6 +115,7 @@ struct vhost_virtqueue { > /* Ring endianness requested by userspace for cross-endian support. */ > bool user_be; > #endif > + u32 busyloop_timeout; > }; > > struct vhost_dev { > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > index ab373191..eaf6c33 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -27,6 +27,11 @@ struct vhost_vring_file { > > }; > > +struct vhost_vring_busyloop_timeout { > + unsigned int index; > + unsigned int timeout; > +}; > + > struct vhost_vring_addr { > unsigned int index; > /* Option flags. */ > @@ -126,6 +131,12 @@ struct vhost_memory { > #define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file) > /* Set eventfd to signal an error */ > #define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file) > +/* Set busy loop timeout */ > +#define VHOST_SET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x23, \ > + struct vhost_vring_busyloop_timeout) > +/* Get busy loop timeout */ > +#define VHOST_GET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x24, \ > + struct vhost_vring_busyloop_timeout) > > /* VHOST_NET specific defines */ > > -- > 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/30/2015 06:44 PM, Michael S. Tsirkin wrote: > On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: >> > This patch tries to poll for new added tx buffer or socket receive >> > queue for a while at the end of tx/rx processing. The maximum time >> > spent on polling were specified through a new kind of vring ioctl. >> > >> > Signed-off-by: Jason Wang <jasowang@redhat.com> > One further enhancement would be to actually poll > the underlying device. This should be reasonably > straight-forward with macvtap (especially in the > passthrough mode). > > Yes, it is. I have some patches to do this by replacing skb_queue_empty() with sk_busy_loop() but for tap. Tests does not show any improvement but some regression. Maybe it's better to test macvtap. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Dec 01, 2015 at 01:17:49PM +0800, Jason Wang wrote: > > > On 11/30/2015 06:44 PM, Michael S. Tsirkin wrote: > > On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: > >> > This patch tries to poll for new added tx buffer or socket receive > >> > queue for a while at the end of tx/rx processing. The maximum time > >> > spent on polling were specified through a new kind of vring ioctl. > >> > > >> > Signed-off-by: Jason Wang <jasowang@redhat.com> > > One further enhancement would be to actually poll > > the underlying device. This should be reasonably > > straight-forward with macvtap (especially in the > > passthrough mode). > > > > > > Yes, it is. I have some patches to do this by replacing > skb_queue_empty() with sk_busy_loop() but for tap. We probably don't want to do this unconditionally, though. > Tests does not show > any improvement but some regression. Did you add code to call sk_mark_napi_id on tap then? sk_busy_loop won't do anything useful without. > Maybe it's better to test macvtap. Same thing ...
On 12/01/2015 10:43 PM, Michael S. Tsirkin wrote: > On Tue, Dec 01, 2015 at 01:17:49PM +0800, Jason Wang wrote: >> >> On 11/30/2015 06:44 PM, Michael S. Tsirkin wrote: >>> On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: >>>>> This patch tries to poll for new added tx buffer or socket receive >>>>> queue for a while at the end of tx/rx processing. The maximum time >>>>> spent on polling were specified through a new kind of vring ioctl. >>>>> >>>>> Signed-off-by: Jason Wang <jasowang@redhat.com> >>> One further enhancement would be to actually poll >>> the underlying device. This should be reasonably >>> straight-forward with macvtap (especially in the >>> passthrough mode). >>> >>> >> Yes, it is. I have some patches to do this by replacing >> skb_queue_empty() with sk_busy_loop() but for tap. > We probably don't want to do this unconditionally, though. > >> Tests does not show >> any improvement but some regression. > Did you add code to call sk_mark_napi_id on tap then? > sk_busy_loop won't do anything useful without. Yes I did. Probably something wrong elsewhere. > >> Maybe it's better to test macvtap. > Same thing ... > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Dec 02, 2015 at 01:04:03PM +0800, Jason Wang wrote: > > > On 12/01/2015 10:43 PM, Michael S. Tsirkin wrote: > > On Tue, Dec 01, 2015 at 01:17:49PM +0800, Jason Wang wrote: > >> > >> On 11/30/2015 06:44 PM, Michael S. Tsirkin wrote: > >>> On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: > >>>>> This patch tries to poll for new added tx buffer or socket receive > >>>>> queue for a while at the end of tx/rx processing. The maximum time > >>>>> spent on polling were specified through a new kind of vring ioctl. > >>>>> > >>>>> Signed-off-by: Jason Wang <jasowang@redhat.com> > >>> One further enhancement would be to actually poll > >>> the underlying device. This should be reasonably > >>> straight-forward with macvtap (especially in the > >>> passthrough mode). > >>> > >>> > >> Yes, it is. I have some patches to do this by replacing > >> skb_queue_empty() with sk_busy_loop() but for tap. > > We probably don't want to do this unconditionally, though. > > > >> Tests does not show > >> any improvement but some regression. > > Did you add code to call sk_mark_napi_id on tap then? > > sk_busy_loop won't do anything useful without. > > Yes I did. Probably something wrong elsewhere. Is this for guest-to-guest? the patch to do napi for tap is still not upstream due to minor performance regression. Want me to repost it? > > > >> Maybe it's better to test macvtap. > > Same thing ... > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/02/2015 08:36 PM, Michael S. Tsirkin wrote: > On Wed, Dec 02, 2015 at 01:04:03PM +0800, Jason Wang wrote: >> >> On 12/01/2015 10:43 PM, Michael S. Tsirkin wrote: >>> On Tue, Dec 01, 2015 at 01:17:49PM +0800, Jason Wang wrote: >>>> On 11/30/2015 06:44 PM, Michael S. Tsirkin wrote: >>>>> On Wed, Nov 25, 2015 at 03:11:29PM +0800, Jason Wang wrote: >>>>>>> This patch tries to poll for new added tx buffer or socket receive >>>>>>> queue for a while at the end of tx/rx processing. The maximum time >>>>>>> spent on polling were specified through a new kind of vring ioctl. >>>>>>> >>>>>>> Signed-off-by: Jason Wang <jasowang@redhat.com> >>>>> One further enhancement would be to actually poll >>>>> the underlying device. This should be reasonably >>>>> straight-forward with macvtap (especially in the >>>>> passthrough mode). >>>>> >>>>> >>>> Yes, it is. I have some patches to do this by replacing >>>> skb_queue_empty() with sk_busy_loop() but for tap. >>> We probably don't want to do this unconditionally, though. >>> >>>> Tests does not show >>>> any improvement but some regression. >>> Did you add code to call sk_mark_napi_id on tap then? >>> sk_busy_loop won't do anything useful without. >> Yes I did. Probably something wrong elsewhere. > Is this for guest-to-guest? Nope. Like you said below, since it requires NAPI so it was external host to guest. > the patch to do napi > for tap is still not upstream due to minor performance > regression. Want me to repost it? Sure, I've played this a little bit in the past too. > >>>> Maybe it's better to test macvtap. >>> Same thing ... >>> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 9eda69e..ce6da77 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -287,6 +287,41 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) rcu_read_unlock_bh(); } +static inline unsigned long busy_clock(void) +{ + return local_clock() >> 10; +} + +static bool vhost_can_busy_poll(struct vhost_dev *dev, + unsigned long endtime) +{ + return likely(!need_resched()) && + likely(!time_after(busy_clock(), endtime)) && + likely(!signal_pending(current)) && + !vhost_has_work(dev) && + single_task_running(); +} + +static int vhost_net_tx_get_vq_desc(struct vhost_net *net, + struct vhost_virtqueue *vq, + struct iovec iov[], unsigned int iov_size, + unsigned int *out_num, unsigned int *in_num) +{ + unsigned long uninitialized_var(endtime); + + if (vq->busyloop_timeout) { + preempt_disable(); + endtime = busy_clock() + vq->busyloop_timeout; + while (vhost_can_busy_poll(vq->dev, endtime) && + !vhost_vq_more_avail(vq->dev, vq)) + cpu_relax(); + preempt_enable(); + } + + return vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), + out_num, in_num, NULL, NULL); +} + /* Expects to be always run from workqueue - which acts as * read-size critical section for our kind of RCU. */ static void handle_tx(struct vhost_net *net) @@ -331,10 +366,9 @@ static void handle_tx(struct vhost_net *net) % UIO_MAXIOV == nvq->done_idx)) break; - head = vhost_get_vq_desc(vq, vq->iov, - ARRAY_SIZE(vq->iov), - &out, &in, - NULL, NULL); + head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, + ARRAY_SIZE(vq->iov), + &out, &in); /* On error, stop handling until the next kick. */ if (unlikely(head < 0)) break; @@ -435,6 +469,34 @@ static int peek_head_len(struct sock *sk) return len; } +static int vhost_net_peek_head_len(struct vhost_net *net, struct sock *sk) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned long uninitialized_var(endtime); + + if (vq->busyloop_timeout) { + mutex_lock(&vq->mutex); + vhost_disable_notify(&net->dev, vq); + + preempt_disable(); + endtime = busy_clock() + vq->busyloop_timeout; + + while (vhost_can_busy_poll(&net->dev, endtime) && + skb_queue_empty(&sk->sk_receive_queue) && + !vhost_vq_more_avail(&net->dev, vq)) + cpu_relax(); + + preempt_enable(); + + if (vhost_enable_notify(&net->dev, vq)) + vhost_poll_queue(&vq->poll); + mutex_unlock(&vq->mutex); + } + + return peek_head_len(sk); +} + /* This is a multi-buffer version of vhost_get_desc, that works if * vq has read descriptors only. * @vq - the relevant virtqueue @@ -553,7 +615,7 @@ static void handle_rx(struct vhost_net *net) vq->log : NULL; mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); - while ((sock_len = peek_head_len(sock->sk))) { + while ((sock_len = vhost_net_peek_head_len(net, sock->sk))) { sock_len += sock_hlen; vhost_len = sock_len + vhost_hlen; headcount = get_rx_bufs(vq, vq->heads, vhost_len, diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index b86c5aa..857af6c 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -285,6 +285,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->memory = NULL; vq->is_le = virtio_legacy_is_little_endian(); vhost_vq_reset_user_be(vq); + vq->busyloop_timeout = 0; } static int vhost_worker(void *data) @@ -747,6 +748,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) struct vhost_vring_state s; struct vhost_vring_file f; struct vhost_vring_addr a; + struct vhost_vring_busyloop_timeout t; u32 idx; long r; @@ -919,6 +921,19 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) case VHOST_GET_VRING_ENDIAN: r = vhost_get_vring_endian(vq, idx, argp); break; + case VHOST_SET_VRING_BUSYLOOP_TIMEOUT: + if (copy_from_user(&t, argp, sizeof(t))) { + r = -EFAULT; + break; + } + vq->busyloop_timeout = t.timeout; + break; + case VHOST_GET_VRING_BUSYLOOP_TIMEOUT: + t.index = idx; + t.timeout = vq->busyloop_timeout; + if (copy_to_user(argp, &t, sizeof(t))) + r = -EFAULT; + break; default: r = -ENOIOCTLCMD; } diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 2f3c57c..4b7d4fa 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -115,6 +115,7 @@ struct vhost_virtqueue { /* Ring endianness requested by userspace for cross-endian support. */ bool user_be; #endif + u32 busyloop_timeout; }; struct vhost_dev { diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index ab373191..eaf6c33 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -27,6 +27,11 @@ struct vhost_vring_file { }; +struct vhost_vring_busyloop_timeout { + unsigned int index; + unsigned int timeout; +}; + struct vhost_vring_addr { unsigned int index; /* Option flags. */ @@ -126,6 +131,12 @@ struct vhost_memory { #define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file) /* Set eventfd to signal an error */ #define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file) +/* Set busy loop timeout */ +#define VHOST_SET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x23, \ + struct vhost_vring_busyloop_timeout) +/* Get busy loop timeout */ +#define VHOST_GET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x24, \ + struct vhost_vring_busyloop_timeout) /* VHOST_NET specific defines */
This patch tries to poll for new added tx buffer or socket receive queue for a while at the end of tx/rx processing. The maximum time spent on polling were specified through a new kind of vring ioctl. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/vhost/net.c | 72 ++++++++++++++++++++++++++++++++++++++++++---- drivers/vhost/vhost.c | 15 ++++++++++ drivers/vhost/vhost.h | 1 + include/uapi/linux/vhost.h | 11 +++++++ 4 files changed, 94 insertions(+), 5 deletions(-)