search for: vhost_add_used_and_signal_n

On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). With the patch we will call at most 2 times > (consider done_idx warp around) compared to N times w/o this patch. > > Signed-off-by: Jason Wang <jasowang at redhat.com> So? Does this help performance then? > --- &gt...

On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). With the patch we will call at most 2 times > (consider done_idx warp around) compared to N times w/o this patch. > > Signed-off-by: Jason Wang <jasowang at redhat.com> So? Does this help performance then? > --- &gt...

On Fri, Aug 30, 2013 at 12:29:18PM +0800, Jason Wang wrote: > We tend to batch the used adding and signaling in vhost_zerocopy_callback() > which may result more than 100 used buffers to be updated in > vhost_zerocopy_signal_used() in some cases. So wwitch to use switch > vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). Which means much more less times of used index > updating and memory barriers. pls put info on perf gain in commit log too > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/net.c | 1...

On Fri, Aug 30, 2013 at 12:29:18PM +0800, Jason Wang wrote: > We tend to batch the used adding and signaling in vhost_zerocopy_callback() > which may result more than 100 used buffers to be updated in > vhost_zerocopy_signal_used() in some cases. So wwitch to use switch > vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). Which means much more less times of used index > updating and memory barriers. pls put info on perf gain in commit log too > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/net.c | 1...

Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to vhost_add_used_and_signal(). With the patch we will call at most 2 times (consider done_idx warp around) compared to N times w/o this patch. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/net.c | 13 ++++++++----- 1 files changed, 8 inser...

We tend to batch the used adding and signaling in vhost_zerocopy_callback() which may result more than 100 used buffers to be updated in vhost_zerocopy_signal_used() in some cases. So wwitch to use vhost_add_used_and_signal_n() to avoid multiple calls to vhost_add_used_and_signal(). Which means much more less times of used index updating and memory barriers. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/net.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-) diff --gi...

On 08/20/2013 10:33 AM, Jason Wang wrote: > On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote: >> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: >>>> Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to >>>> vhost_add_used_and_signal(). With the patch we will call at most 2 times >>>> (consider done_idx warp around) compared to N times w/o this patch. >>>> >>>> Signed-off-by: Jason Wang <jasowang at redhat.com> >...

On 08/20/2013 10:33 AM, Jason Wang wrote: > On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote: >> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: >>>> Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to >>>> vhost_add_used_and_signal(). With the patch we will call at most 2 times >>>> (consider done_idx warp around) compared to N times w/o this patch. >>>> >>>> Signed-off-by: Jason Wang <jasowang at redhat.com> >...

On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote: > On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: >> > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to >> > vhost_add_used_and_signal(). With the patch we will call at most 2 times >> > (consider done_idx warp around) compared to N times w/o this patch. >> > >> > Signed-off-by: Jason Wang <jasowang at redhat.com> > So? Does t...

...c | 13 +++++++++++++ > drivers/vhost/vhost.h | 1 + > 2 files changed, 14 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 163b365..4f45a03 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1633,6 +1633,19 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, > } > EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); > > +bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq) > +{ > + __virtio16 avail_idx; > + int r; > + > + r = __get_user(avail_idx, &vq->avail->idx); > +...

...c | 13 +++++++++++++ > drivers/vhost/vhost.h | 1 + > 2 files changed, 14 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 163b365..4f45a03 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1633,6 +1633,19 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, > } > EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); > > +bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq) > +{ > + __virtio16 avail_idx; > + int r; > + > + r = __get_user(avail_idx, &vq->avail->idx); > +...

...atic int sk_has_rx_data(struct sock *sk) return skb_queue_empty(&sk->sk_receive_queue); } +static void vhost_rx_signal_used(struct vhost_net_virtqueue *nvq) +{ + struct vhost_virtqueue *vq = &nvq->vq; + struct vhost_dev *dev = vq->dev; + + if (!nvq->done_idx) + return; + + vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); + nvq->done_idx = 0; +} + static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk) { struct vhost_net_virtqueue *rvq = &net->vqs[VHOST_NET_VQ_RX]; @@ -635,6 +649,8 @@ static int vhost_net_rx_peek_head_len(struct vhost_net...

...s(vq, vq->heads + nheads, vhost_len, &in, vq_log, &log, likely(mergeable) ? UIO_MAXIOV : 1); /* On error, stop handling until the next kick. */ @@ -844,8 +844,12 @@ static void handle_rx(struct vhost_net *net) vhost_discard_vq_desc(vq, headcount); goto out; } - vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, - headcount); + nheads += headcount; + if (nheads > VHOST_RX_BATCH) { + vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, + nheads); + nheads = 0; + } if (unlikely(vq_log)) vhost_log_write(vq, vq_log, log, vhost_len...

...igned int head, int len); +int vhost_add_used_n(struct vhost_virtqueue *, bool urgent, + struct vring_used_elem *heads, unsigned count); +void vhost_add_used_and_signal(struct vhost_dev *, + struct vhost_virtqueue *, + bool urgent, unsigned int id, int len); void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, - struct vring_used_elem *heads, unsigned count); + bool urgent, + struct vring_used_elem *heads, unsigned count); void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); void vhost_disable_notify(struct vhost_dev *, struct v...

Below should be useful for some experiments Jason is doing. I thought I'd send it out for early review/feedback. Compiled-only at this point. event idx feature allows us to defer interrupts until a specific # of descriptors were used. Sometimes it might be useful to get an interrupt after a specific descriptor, regardless. This adds a descriptor flag for this, and an API to create an urgent

Below should be useful for some experiments Jason is doing. I thought I'd send it out for early review/feedback. Compiled-only at this point. event idx feature allows us to defer interrupts until a specific # of descriptors were used. Sometimes it might be useful to get an interrupt after a specific descriptor, regardless. This adds a descriptor flag for this, and an API to create an urgent

...st.h | 1 + >> 2 files changed, 18 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> index 163b365..b86c5aa 100644 >> --- a/drivers/vhost/vhost.c >> +++ b/drivers/vhost/vhost.c >> @@ -1633,10 +1633,25 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, >> } >> EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); >> >> +bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq) >> +{ >> + __virtio16 avail_idx; >> + int r; >> + >> + r = __get_user(avail_idx...

...redhat.com> --- drivers/vhost/vhost.c | 13 +++++++++++++ drivers/vhost/vhost.h | 1 + 2 files changed, 14 insertions(+) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 163b365..4f45a03 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1633,6 +1633,19 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, } EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); +bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq) +{ + __virtio16 avail_idx; + int r; + + r = __get_user(avail_idx, &vq->avail->idx); + if (r) + return false; + + return vhost16_to_cpu...

...st.h | 1 + >> 2 files changed, 18 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> index 163b365..b86c5aa 100644 >> --- a/drivers/vhost/vhost.c >> +++ b/drivers/vhost/vhost.c >> @@ -1633,10 +1633,25 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, >> } >> EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); >> >> +bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq) >> +{ >> + __virtio16 avail_idx; >> + int r; >> + >> + r = __get_user(avail_idx...

...st_add_used_and_signal(struct vhost_dev *dev, - struct vhost_virtqueue *vq, - unsigned int head, int len) -{ - vhost_add_used(vq, head, len); - vhost_signal(dev, vq); -} -EXPORT_SYMBOL_GPL(vhost_add_used_and_signal); - -/* multi-buffer version of vhost_add_used_and_signal */ -void vhost_add_used_and_signal_n(struct vhost_dev *dev, - struct vhost_virtqueue *vq, - struct vring_used_elem *heads, unsigned count) -{ - vhost_add_used_n(vq, heads, count); - vhost_signal(dev, vq); -} -EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); - /* return true if we're sure that avaiable ring is empty */ boo...