On 2018年06月20日 21:28, Tonghao Zhang wrote:
This patch improves the guest receive performance from
host. On the handle_tx side, we poll the sock receive
queue at the same time. handle_rx do that in the same way.
we set the poll-us=100 us and use the iperf3 to test
its throughput. The iperf3 command is shown as below.
iperf3 -s -D
iperf3 -c 192.168.1.100 -i 1 -P 10 -t 10 -M 1400 --bandwidth 100000M
* With the patch: 21.1 Gbits/sec
* Without the patch: 12.7 Gbits/sec
Thanks a lot for the patch. But looks like it needs some work to avoid
e.g deadlock.
E.g in vhost_process_iotlb_msg() we call vhost_dev_lock_vqs() which did:
for (i = 0; i < d->nvqs; ++i)
mutex_lock_nested(&d->vqs[i]->mutex, i);
I believe we need to change the code to lock the vq one by one like the
attached (only compile test).
Signed-off-by: Tonghao Zhang <zhangtonghao@xxxxxxxxxxxxxxx>
---
drivers/vhost/net.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index e7cf7d2..9364ede 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -429,22 +429,43 @@ static int vhost_net_enable_vq(struct vhost_net *n,
return vhost_poll_start(poll, sock->file);
}
+static int sk_has_rx_data(struct sock *sk);
+
How about move sk_has_rx_data() here.
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);
+ struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
+ struct vhost_virtqueue *rvq = &nvq->vq;
+ struct socket *sock = rvq->private_data;
+
int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
out_num, in_num, NULL, NULL);
if (r == vq->num && vq->busyloop_timeout) {
+ mutex_lock_nested(&rvq->mutex, 1);
+
+ vhost_disable_notify(&net->dev, rvq);
+
preempt_disable();
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(vq->dev, endtime) &&
+ !(sock && sk_has_rx_data(sock->sk)) &&
vhost_vq_avail_empty(vq->dev, vq))
cpu_relax();
preempt_enable();
+
+ if (sock && sk_has_rx_data(sock->sk))
+ vhost_poll_queue(&rvq->poll);
+ else if (unlikely(vhost_enable_notify(&net->dev, rvq))) {
+ vhost_disable_notify(&net->dev, rvq);
+ vhost_poll_queue(&rvq->poll);
+ }
+
+ mutex_unlock(&rvq->mutex);
Some kinds of code duplication, can we try to unify them?
Btw, net-next is closed, so you need resubmit after it was open and use
a "net-next" as the prefix of the patch.
Thanks
+
r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
out_num, in_num, NULL, NULL);
}
>From 383fe9d98420d92a632dc554969b4b1716017ba2 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Thu, 21 Jun 2018 13:58:31 +0800
Subject: [PATCH] vhost: lock vqs one by one
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 23 ++++++-----------------
1 file changed, 6 insertions(+), 17 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e5bc4bb..937252d 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -294,8 +294,11 @@ static void vhost_vq_meta_reset(struct vhost_dev *d)
{
int i;
- for (i = 0; i < d->nvqs; ++i)
+ for (i = 0; i < d->nvqs; ++i) {
+ mutex_lock(&d->vqs[i]->mutex);
__vhost_vq_meta_reset(d->vqs[i]);
+ mutex_unlock(&d->vqs[i]->mutex);
+ }
}
static void vhost_vq_reset(struct vhost_dev *dev,
@@ -855,20 +858,6 @@ static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
#define vhost_get_used(vq, x, ptr) \
vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
-static void vhost_dev_lock_vqs(struct vhost_dev *d)
-{
- int i = 0;
- for (i = 0; i < d->nvqs; ++i)
- mutex_lock_nested(&d->vqs[i]->mutex, i);
-}
-
-static void vhost_dev_unlock_vqs(struct vhost_dev *d)
-{
- int i = 0;
- for (i = 0; i < d->nvqs; ++i)
- mutex_unlock(&d->vqs[i]->mutex);
-}
-
static int vhost_new_umem_range(struct vhost_umem *umem,
u64 start, u64 size, u64 end,
u64 userspace_addr, int perm)
@@ -918,7 +907,9 @@ static void vhost_iotlb_notify_vq(struct vhost_dev *d,
if (msg->iova <= vq_msg->iova &&
msg->iova + msg->size - 1 > vq_msg->iova &&
vq_msg->type == VHOST_IOTLB_MISS) {
+ mutex_lock(&node->vq->mutex);
vhost_poll_queue(&node->vq->poll);
+ mutex_unlock(&node->vq->mutex);
list_del(&node->node);
kfree(node);
}
@@ -950,7 +941,6 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
int ret = 0;
mutex_lock(&dev->mutex);
- vhost_dev_lock_vqs(dev);
switch (msg->type) {
case VHOST_IOTLB_UPDATE:
if (!dev->iotlb) {
@@ -984,7 +974,6 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
break;
}
- vhost_dev_unlock_vqs(dev);
mutex_unlock(&dev->mutex);
return ret;
--
2.7.4
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