* Re: [dpdk-dev] [PATCH v6] vhost: support virtqueue interrupt/notification suppression
2017-12-26 17:43 ` [dpdk-dev] [PATCH v6] " Junjie Chen
@ 2018-01-05 5:25 ` Wang, Xiao W
2018-01-08 14:06 ` Yuanhan Liu
2018-01-09 11:03 ` [dpdk-dev] [PATCH v7] " Junjie Chen
2 siblings, 0 replies; 12+ messages in thread
From: Wang, Xiao W @ 2018-01-05 5:25 UTC (permalink / raw)
To: Chen, Junjie J, yliu, maxime.coquelin, Bie, Tiwei; +Cc: dev
Hi,
> -----Original Message-----
> From: Chen, Junjie J
> Sent: Wednesday, December 27, 2017 1:43 AM
> To: Wang, Xiao W <xiao.w.wang@intel.com>; yliu@fridaylinux.org;
> maxime.coquelin@redhat.com; Bie, Tiwei <tiwei.bie@intel.com>
> Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> Subject: [PATCH v6] vhost: support virtqueue interrupt/notification
> suppression
>
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
>
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
>
> This patch is to enable this feature in vhost.
>
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
>
> v6:
> Use volatile qualifier to access avail event idx.
>
> v5:
> Remove updating avail event index in backend.
>
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
>
> ---
> lib/librte_vhost/vhost.h | 3 +++
> lib/librte_vhost/virtio_net.c | 46 +++++++++++++++++++++++++++++-------------
> -
> 2 files changed, 34 insertions(+), 15 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 1cc81c1..fc41c20 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -103,6 +103,8 @@ struct vhost_virtqueue {
>
> uint16_t last_avail_idx;
> uint16_t last_used_idx;
> + /* Last used index we notify to front end. */
> + uint16_t signalled_used;
> #define VIRTIO_INVALID_EVENTFD (-1)
> #define VIRTIO_UNINITIALIZED_EVENTFD (-2)
>
> @@ -211,6 +213,7 @@ struct vhost_msg {
> (1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
> (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
> (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
> + (1ULL << VIRTIO_RING_F_EVENT_IDX) | \
> (1ULL << VIRTIO_NET_F_MTU) | \
> (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 6fee16e..f5777fc 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -52,6 +52,34 @@
>
> #define MAX_BATCH_LEN 256
>
> +#define vhost_used_event(vr) \
> + (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +static __rte_always_inline void
> +vhost_notify(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{
> + /* Don't notify guest if we don't reach index specified by guest. */
> + if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> + uint16_t old = vq->signalled_used;
> + uint16_t new = vq->last_used_idx;
> +
> + LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d,
> new=%d\n",
> + __func__,
> + vhost_used_event(vq),
> + old, new);
> + if (vring_need_event(vhost_used_event(vq), new, old)
> + && (vq->callfd >= 0)) {
> + vq->signalled_used = vq->last_used_idx;
> + eventfd_write(vq->callfd, (eventfd_t) 1);
> + }
> + } else {
> + /* Kick the guest if necessary. */
> + if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> + && (vq->callfd >= 0))
> + eventfd_write(vq->callfd, (eventfd_t)1);
> + }
> +}
> +
> static bool
> is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
> {
> @@ -410,11 +438,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t
> queue_id,
>
> /* flush used->idx update before we read avail->flags. */
> rte_mb();
> -
> - /* Kick the guest if necessary. */
> - if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> - && (vq->callfd >= 0))
> - eventfd_write(vq->callfd, (eventfd_t)1);
> + vhost_notify(dev, vq);
> out:
> if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> vhost_user_iotlb_rd_unlock(vq);
> @@ -704,11 +728,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
>
> /* flush used->idx update before we read avail->flags. */
> rte_mb();
> -
> - /* Kick the guest if necessary. */
> - if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> - && (vq->callfd >= 0))
> - eventfd_write(vq->callfd, (eventfd_t)1);
> + vhost_notify(dev, vq);
> }
>
> out:
> @@ -1106,11 +1126,7 @@ update_used_idx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> vq->used->idx += count;
> vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
> sizeof(vq->used->idx));
> -
> - /* Kick guest if required. */
> - if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> - && (vq->callfd >= 0))
> - eventfd_write(vq->callfd, (eventfd_t)1);
> + vhost_notify(dev, vq);
> }
>
> static __rte_always_inline struct zcopy_mbuf *
> --
> 2.0.1
Reviewed-by: Xiao Wang <xiao.w.wang@intel.com>
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [dpdk-dev] [PATCH v6] vhost: support virtqueue interrupt/notification suppression
2017-12-26 17:43 ` [dpdk-dev] [PATCH v6] " Junjie Chen
2018-01-05 5:25 ` Wang, Xiao W
@ 2018-01-08 14:06 ` Yuanhan Liu
2018-01-09 2:12 ` Chen, Junjie J
2018-01-09 11:03 ` [dpdk-dev] [PATCH v7] " Junjie Chen
2 siblings, 1 reply; 12+ messages in thread
From: Yuanhan Liu @ 2018-01-08 14:06 UTC (permalink / raw)
To: Junjie Chen; +Cc: xiao.w.wang, maxime.coquelin, tiwei.bie, dev, Yao, Lei A
On Tue, Dec 26, 2017 at 12:43:10PM -0500, Junjie Chen wrote:
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
>
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
>
> This patch is to enable this feature in vhost.
>
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
You need put "---" before the change log. Otherwise, it will be tracked in
the commit log.
> +#define vhost_used_event(vr) \
> + (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +static __rte_always_inline void
> +vhost_notify(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{
> + /* Don't notify guest if we don't reach index specified by guest. */
> + if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> + uint16_t old = vq->signalled_used;
> + uint16_t new = vq->last_used_idx;
> +
> + LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
> + __func__,
> + vhost_used_event(vq),
> + old, new);
> + if (vring_need_event(vhost_used_event(vq), new, old)
It's a bit weird that you use one from the standard linux header file
(vring_need_event), while you define you own one (vhost_used_event).
Note that the system header file also has "vring_used_event()" defined.
Besides that, I have few more comments (and some requirements):
- It'd be much better if there is a Tested-by tag. Expeclitly,
I'm asking a test with Linux kernel virtio-net driver in guest.
- I also hope you could have done a build test on some old distributions.
AFAIK, the two macros (vring_need_event and vring_used_event) come
from kernel 3.0 (or above). Any kernel older than that would fail
the build.
- I'd be great if you could make a new one based on top of my latest
tree: I have just applied a patchset that should conflict with this
one.
--yliu
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [dpdk-dev] [PATCH v6] vhost: support virtqueue interrupt/notification suppression
2018-01-08 14:06 ` Yuanhan Liu
@ 2018-01-09 2:12 ` Chen, Junjie J
2018-01-09 2:29 ` Yuanhan Liu
0 siblings, 1 reply; 12+ messages in thread
From: Chen, Junjie J @ 2018-01-09 2:12 UTC (permalink / raw)
To: Yuanhan Liu; +Cc: Wang, Xiao W, maxime.coquelin, Bie, Tiwei, dev, Yao, Lei A
Hi
> -----Original Message-----
> From: Yuanhan Liu [mailto:yliu@fridaylinux.org]
> Sent: Monday, January 8, 2018 10:07 PM
> To: Chen, Junjie J <junjie.j.chen@intel.com>
> Cc: Wang, Xiao W <xiao.w.wang@intel.com>; maxime.coquelin@redhat.com;
> Bie, Tiwei <tiwei.bie@intel.com>; dev@dpdk.org; Yao, Lei A
> <lei.a.yao@intel.com>
> Subject: Re: [PATCH v6] vhost: support virtqueue interrupt/notification
> suppression
>
> On Tue, Dec 26, 2017 at 12:43:10PM -0500, Junjie Chen wrote:
> > The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit
> > is negotiated. The driver set vring flags to 0, and MAY use used_event
> > in available ring to advise device interrupt util reach an index
> > specified by used_event. The device ignore the lower bit of vring
> > flags, and send an interrupt when index reach used_event.
> >
> > The device can suppress notification in a manner analogous to the ways
> > driver suppress interrupt. The device manipulates flags or avail_event
> > in the used ring in the same way the driver manipulates flags or
> > used_event in available ring.
> >
> > This patch is to enable this feature in vhost.
> >
> > Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
>
> You need put "---" before the change log. Otherwise, it will be tracked in the
> commit log.
Will update this.
>
> > +#define vhost_used_event(vr) \
> > + (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> > +
> > +static __rte_always_inline void
> > +vhost_notify(struct virtio_net *dev, struct vhost_virtqueue *vq) {
> > + /* Don't notify guest if we don't reach index specified by guest. */
> > + if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> > + uint16_t old = vq->signalled_used;
> > + uint16_t new = vq->last_used_idx;
> > +
> > + LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d,
> new=%d\n",
> > + __func__,
> > + vhost_used_event(vq),
> > + old, new);
> > + if (vring_need_event(vhost_used_event(vq), new, old)
>
> It's a bit weird that you use one from the standard linux header file
> (vring_need_event), while you define you own one (vhost_used_event).
> Note that the system header file also has "vring_used_event()" defined.
The vring_used_event is defined and used for virtio in kernel, kernel defines a vhost_used_event in vhost.c for vhost, so I just use a separated macro for vhost end.
I'd like to define both vhost_need_event and vhost_used_event in vhost.h to remove potential build issue in old linux distribution and also to keep consistent. Is that OK for you?
>
> Besides that, I have few more comments (and some requirements):
>
> - It'd be much better if there is a Tested-by tag. Expeclitly,
> I'm asking a test with Linux kernel virtio-net driver in guest.
Sure.
>
> - I also hope you could have done a build test on some old distributions.
> AFAIK, the two macros (vring_need_event and vring_used_event) come
> from kernel 3.0 (or above). Any kernel older than that would fail
> the build.
>
> - I'd be great if you could make a new one based on top of my latest
> tree: I have just applied a patchset that should conflict with this
> one.
Sure, will do this.
>
> --yliu
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [dpdk-dev] [PATCH v6] vhost: support virtqueue interrupt/notification suppression
2018-01-09 2:12 ` Chen, Junjie J
@ 2018-01-09 2:29 ` Yuanhan Liu
0 siblings, 0 replies; 12+ messages in thread
From: Yuanhan Liu @ 2018-01-09 2:29 UTC (permalink / raw)
To: Chen, Junjie J; +Cc: Wang, Xiao W, maxime.coquelin, Bie, Tiwei, dev, Yao, Lei A
On Tue, Jan 09, 2018 at 02:12:02AM +0000, Chen, Junjie J wrote:
> > > + if (vring_need_event(vhost_used_event(vq), new, old)
> >
> > It's a bit weird that you use one from the standard linux header file
> > (vring_need_event), while you define you own one (vhost_used_event).
> > Note that the system header file also has "vring_used_event()" defined.
> The vring_used_event is defined and used for virtio in kernel, kernel defines a vhost_used_event in vhost.c for vhost, so I just use a separated macro for vhost end.
>
> I'd like to define both vhost_need_event and vhost_used_event in vhost.h to remove potential build issue in old linux distribution and also to keep consistent. Is that OK for you?
Yes.
--yliu
^ permalink raw reply [flat|nested] 12+ messages in thread
* [dpdk-dev] [PATCH v7] vhost: support virtqueue interrupt/notification suppression
2017-12-26 17:43 ` [dpdk-dev] [PATCH v6] " Junjie Chen
2018-01-05 5:25 ` Wang, Xiao W
2018-01-08 14:06 ` Yuanhan Liu
@ 2018-01-09 11:03 ` Junjie Chen
2018-01-09 7:34 ` Yao, Lei A
2018-01-09 8:56 ` Maxime Coquelin
2 siblings, 2 replies; 12+ messages in thread
From: Junjie Chen @ 2018-01-09 11:03 UTC (permalink / raw)
To: yliu, maxime.coquelin, xiao.w.wang, tiwei.bie, lei.a.yao; +Cc: dev, Junjie Chen
The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
negotiated. The driver set vring flags to 0, and MAY use used_event in
available ring to advise device interrupt util reach an index specified
by used_event. The device ignore the lower bit of vring flags, and send
an interrupt when index reach used_event.
The device can suppress notification in a manner analogous to the ways
driver suppress interrupt. The device manipulates flags or avail_event in
the used ring in the same way the driver manipulates flags or used_event in
available ring.
Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
---
v7:
Add vhost_need_event definition and update code for next virtio.
v6:
Use volatile qualifier to access avail event idx.
v5:
Remove updating avail event index in backend.
v2-v4:
Use definition of VIRTIO_F_EVENT_IDX from kernel.
lib/librte_vhost/vhost.c | 2 +-
lib/librte_vhost/vhost.h | 44 ++++++++++++++++++++++++++++++++++++++-----
lib/librte_vhost/virtio_net.c | 6 +++---
3 files changed, 43 insertions(+), 9 deletions(-)
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 6f7ef7f..400caa0 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -538,7 +538,7 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
if (!vq)
return -1;
- vhost_vring_call(vq);
+ vhost_vring_call(dev, vq);
return 0;
}
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1d9366e..ec79991 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -103,6 +103,8 @@ struct vhost_virtqueue {
uint16_t last_avail_idx;
uint16_t last_used_idx;
+ /* Last used index we notify to front end. */
+ uint16_t signalled_used;
#define VIRTIO_INVALID_EVENTFD (-1)
#define VIRTIO_UNINITIALIZED_EVENTFD (-2)
@@ -214,6 +216,7 @@ struct vhost_msg {
(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
(1ULL << VIRTIO_NET_F_GUEST_UFO) | \
(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+ (1ULL << VIRTIO_RING_F_EVENT_IDX) | \
(1ULL << VIRTIO_NET_F_MTU) | \
(1ULL << VIRTIO_F_IOMMU_PLATFORM))
@@ -399,16 +402,47 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
return __vhost_iova_to_vva(dev, vq, iova, size, perm);
}
+#define vhost_used_event(vr) \
+ (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
+
+/*
+ * The following is used with VIRTIO_RING_F_EVENT_IDX.
+ * Assuming a given event_idx value from the other size, if we have
+ * just incremented index from old to new_idx, should we trigger an
+ * event?
+ */
+static __rte_always_inline int
+vhost_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
+{
+ return (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx - old);
+}
+
static __rte_always_inline void
-vhost_vring_call(struct vhost_virtqueue *vq)
+vhost_vring_call(struct virtio_net *dev, struct vhost_virtqueue *vq)
{
/* Flush used->idx update before we read avail->flags. */
rte_mb();
- /* Kick the guest if necessary. */
- if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
- && (vq->callfd >= 0))
- eventfd_write(vq->callfd, (eventfd_t)1);
+ /* Don't kick guest if we don't reach index specified by guest. */
+ if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+ uint16_t old = vq->signalled_used;
+ uint16_t new = vq->last_used_idx;
+
+ LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
+ __func__,
+ vhost_used_event(vq),
+ old, new);
+ if (vhost_need_event(vhost_used_event(vq), new, old)
+ && (vq->callfd >= 0)) {
+ vq->signalled_used = vq->last_used_idx;
+ eventfd_write(vq->callfd, (eventfd_t) 1);
+ }
+ } else {
+ /* Kick the guest if necessary. */
+ if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+ && (vq->callfd >= 0))
+ eventfd_write(vq->callfd, (eventfd_t)1);
+ }
}
#endif /* _VHOST_NET_CDEV_H_ */
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index eb496e1..d0f9221 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -413,7 +413,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
offsetof(struct vring_used, idx),
sizeof(vq->used->idx));
- vhost_vring_call(vq);
+ vhost_vring_call(dev, vq);
out:
if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
vhost_user_iotlb_rd_unlock(vq);
@@ -700,7 +700,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
if (likely(vq->shadow_used_idx)) {
flush_shadow_used_ring(dev, vq);
- vhost_vring_call(vq);
+ vhost_vring_call(dev, vq);
}
out:
@@ -1104,7 +1104,7 @@ update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
vq->used->idx += count;
vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
sizeof(vq->used->idx));
- vhost_vring_call(vq);
+ vhost_vring_call(dev, vq);
}
static __rte_always_inline struct zcopy_mbuf *
--
2.0.1
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [dpdk-dev] [PATCH v7] vhost: support virtqueue interrupt/notification suppression
2018-01-09 11:03 ` [dpdk-dev] [PATCH v7] " Junjie Chen
@ 2018-01-09 7:34 ` Yao, Lei A
2018-01-09 12:58 ` Yuanhan Liu
2018-01-09 8:56 ` Maxime Coquelin
1 sibling, 1 reply; 12+ messages in thread
From: Yao, Lei A @ 2018-01-09 7:34 UTC (permalink / raw)
To: Chen, Junjie J, yliu, maxime.coquelin, Wang, Xiao W, Bie, Tiwei; +Cc: dev
> -----Original Message-----
> From: Chen, Junjie J
> Sent: Tuesday, January 9, 2018 7:04 PM
> To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; Wang, Xiao W
> <xiao.w.wang@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>; Yao, Lei A
> <lei.a.yao@intel.com>
> Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> Subject: [PATCH v7] vhost: support virtqueue interrupt/notification
> suppression
>
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
>
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
>
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
Tested-by: Lei Yao <lei.a.yao@intel.com>
VM2VM Iperf test has been executed with virtio-net driver after apply this patch.
No performance drop.
CPU: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
Host OS: Ubuntu 16.04
Guest OS: Ubuntu 16.04
Kernel: 4.4.0
> ---
> v7:
> Add vhost_need_event definition and update code for next virtio.
>
> v6:
> Use volatile qualifier to access avail event idx.
>
> v5:
> Remove updating avail event index in backend.
>
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
>
> lib/librte_vhost/vhost.c | 2 +-
> lib/librte_vhost/vhost.h | 44
> ++++++++++++++++++++++++++++++++++++++-----
> lib/librte_vhost/virtio_net.c | 6 +++---
> 3 files changed, 43 insertions(+), 9 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index 6f7ef7f..400caa0 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -538,7 +538,7 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
> if (!vq)
> return -1;
>
> - vhost_vring_call(vq);
> + vhost_vring_call(dev, vq);
> return 0;
> }
>
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 1d9366e..ec79991 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -103,6 +103,8 @@ struct vhost_virtqueue {
>
> uint16_t last_avail_idx;
> uint16_t last_used_idx;
> + /* Last used index we notify to front end. */
> + uint16_t signalled_used;
> #define VIRTIO_INVALID_EVENTFD (-1)
> #define VIRTIO_UNINITIALIZED_EVENTFD (-2)
>
> @@ -214,6 +216,7 @@ struct vhost_msg {
> (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
> (1ULL << VIRTIO_NET_F_GUEST_UFO) | \
> (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> \
> + (1ULL << VIRTIO_RING_F_EVENT_IDX) | \
> (1ULL << VIRTIO_NET_F_MTU) | \
> (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>
> @@ -399,16 +402,47 @@ vhost_iova_to_vva(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> return __vhost_iova_to_vva(dev, vq, iova, size, perm);
> }
>
> +#define vhost_used_event(vr) \
> + (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +/*
> + * The following is used with VIRTIO_RING_F_EVENT_IDX.
> + * Assuming a given event_idx value from the other size, if we have
> + * just incremented index from old to new_idx, should we trigger an
> + * event?
> + */
> +static __rte_always_inline int
> +vhost_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
> +{
> + return (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx -
> old);
> +}
> +
> static __rte_always_inline void
> -vhost_vring_call(struct vhost_virtqueue *vq)
> +vhost_vring_call(struct virtio_net *dev, struct vhost_virtqueue *vq)
> {
> /* Flush used->idx update before we read avail->flags. */
> rte_mb();
>
> - /* Kick the guest if necessary. */
> - if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> - && (vq->callfd >= 0))
> - eventfd_write(vq->callfd, (eventfd_t)1);
> + /* Don't kick guest if we don't reach index specified by guest. */
> + if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> + uint16_t old = vq->signalled_used;
> + uint16_t new = vq->last_used_idx;
> +
> + LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d,
> old=%d, new=%d\n",
> + __func__,
> + vhost_used_event(vq),
> + old, new);
> + if (vhost_need_event(vhost_used_event(vq), new, old)
> + && (vq->callfd >= 0)) {
> + vq->signalled_used = vq->last_used_idx;
> + eventfd_write(vq->callfd, (eventfd_t) 1);
> + }
> + } else {
> + /* Kick the guest if necessary. */
> + if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> + && (vq->callfd >= 0))
> + eventfd_write(vq->callfd, (eventfd_t)1);
> + }
> }
>
> #endif /* _VHOST_NET_CDEV_H_ */
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index eb496e1..d0f9221 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -413,7 +413,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t
> queue_id,
> offsetof(struct vring_used, idx),
> sizeof(vq->used->idx));
>
> - vhost_vring_call(vq);
> + vhost_vring_call(dev, vq);
> out:
> if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> vhost_user_iotlb_rd_unlock(vq);
> @@ -700,7 +700,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
>
> if (likely(vq->shadow_used_idx)) {
> flush_shadow_used_ring(dev, vq);
> - vhost_vring_call(vq);
> + vhost_vring_call(dev, vq);
> }
>
> out:
> @@ -1104,7 +1104,7 @@ update_used_idx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> vq->used->idx += count;
> vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
> sizeof(vq->used->idx));
> - vhost_vring_call(vq);
> + vhost_vring_call(dev, vq);
> }
>
> static __rte_always_inline struct zcopy_mbuf *
> --
> 2.0.1
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [dpdk-dev] [PATCH v7] vhost: support virtqueue interrupt/notification suppression
2018-01-09 7:34 ` Yao, Lei A
@ 2018-01-09 12:58 ` Yuanhan Liu
0 siblings, 0 replies; 12+ messages in thread
From: Yuanhan Liu @ 2018-01-09 12:58 UTC (permalink / raw)
To: Yao, Lei A; +Cc: Chen, Junjie J, maxime.coquelin, Wang, Xiao W, Bie, Tiwei, dev
On Tue, Jan 09, 2018 at 07:34:17AM +0000, Yao, Lei A wrote:
>
>
> > -----Original Message-----
> > From: Chen, Junjie J
> > Sent: Tuesday, January 9, 2018 7:04 PM
> > To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; Wang, Xiao W
> > <xiao.w.wang@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>; Yao, Lei A
> > <lei.a.yao@intel.com>
> > Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> > Subject: [PATCH v7] vhost: support virtqueue interrupt/notification
> > suppression
> >
> > The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> > negotiated. The driver set vring flags to 0, and MAY use used_event in
> > available ring to advise device interrupt util reach an index specified
> > by used_event. The device ignore the lower bit of vring flags, and send
> > an interrupt when index reach used_event.
> >
> > The device can suppress notification in a manner analogous to the ways
> > driver suppress interrupt. The device manipulates flags or avail_event in
> > the used ring in the same way the driver manipulates flags or used_event in
> > available ring.
> >
> > Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> Tested-by: Lei Yao <lei.a.yao@intel.com>
Applied to dpdk-next-virtio.
Thanks.
--yliu
> VM2VM Iperf test has been executed with virtio-net driver after apply this patch.
> No performance drop.
> CPU: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
> Host OS: Ubuntu 16.04
> Guest OS: Ubuntu 16.04
> Kernel: 4.4.0
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [dpdk-dev] [PATCH v7] vhost: support virtqueue interrupt/notification suppression
2018-01-09 11:03 ` [dpdk-dev] [PATCH v7] " Junjie Chen
2018-01-09 7:34 ` Yao, Lei A
@ 2018-01-09 8:56 ` Maxime Coquelin
1 sibling, 0 replies; 12+ messages in thread
From: Maxime Coquelin @ 2018-01-09 8:56 UTC (permalink / raw)
To: Junjie Chen, yliu, xiao.w.wang, tiwei.bie, lei.a.yao; +Cc: dev
On 01/09/2018 12:03 PM, Junjie Chen wrote:
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
>
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
>
> Signed-off-by: Junjie Chen<junjie.j.chen@intel.com>
> ---
> v7:
> Add vhost_need_event definition and update code for next virtio.
>
> v6:
> Use volatile qualifier to access avail event idx.
>
> v5:
> Remove updating avail event index in backend.
>
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
>
> lib/librte_vhost/vhost.c | 2 +-
> lib/librte_vhost/vhost.h | 44 ++++++++++++++++++++++++++++++++++++++-----
> lib/librte_vhost/virtio_net.c | 6 +++---
> 3 files changed, 43 insertions(+), 9 deletions(-)
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Thanks,
Maxime
^ permalink raw reply [flat|nested] 12+ messages in thread