From 5dae785a82c1a8c05b5b4f9709bd9ce658dcf1b6 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 29 Jul 2008 09:58:35 -0500 Subject: [PATCH] lguest: net block unneeded receive queue update notifications Number of exits transmitting 10GB Guest->Host before: network xmit 7858610 recv 118136 After: network xmit 7750233 recv 1 Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 31a688e105ca..46f4c5b09e9e 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -933,6 +933,11 @@ static bool handle_tun_input(int fd, struct device *dev) /* FIXME: Actually want DRIVER_ACTIVE here. */ if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) warn("network: no dma buffer!"); + + /* Now tell it we want to know if new things appear. */ + dev->vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY; + wmb(); + /* We'll turn this back on if input buffers are registered. */ return false; } else if (out_num) @@ -969,6 +974,13 @@ static void enable_fd(int fd, struct virtqueue *vq) write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd)); } +static void net_enable_fd(int fd, struct virtqueue *vq) +{ + /* We don't need to know again when Guest refills receive buffer. */ + vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY; + enable_fd(fd, vq); +} + /* When the Guest tells us they updated the status field, we handle it. */ static void update_device_status(struct device *dev) { @@ -1426,7 +1438,7 @@ static void setup_tun_net(char *arg) /* Network devices need a receive and a send queue, just like * console. */ - add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd); + add_virtqueue(dev, VIRTQUEUE_NUM, net_enable_fd); add_virtqueue(dev, VIRTQUEUE_NUM, handle_net_output); /* We need a socket to perform the magic network ioctls to bring up the