search for: sk_wmem_alloc

...ld transmitted packets in ndo_start_xmit() currently, so any > > packet must be orphaned also there. This was used to reduce the overhead of > > tx interrupt to achieve better performance. But this may not work for some > > protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to > > implement various optimization for small packets stream such as TCP small > > queue and auto corking. But orphaning packets early in ndo_start_xmit() > > disable such things more or less since sk_wmem_alloc was not accurate. This > > lead extra low throughput for TCP...

...ld transmitted packets in ndo_start_xmit() currently, so any > > packet must be orphaned also there. This was used to reduce the overhead of > > tx interrupt to achieve better performance. But this may not work for some > > protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to > > implement various optimization for small packets stream such as TCP small > > queue and auto corking. But orphaning packets early in ndo_start_xmit() > > disable such things more or less since sk_wmem_alloc was not accurate. This > > lead extra low throughput for TCP...

...ld transmitted packets in ndo_start_xmit() currently, so any > > packet must be orphaned also there. This was used to reduce the overhead of > > tx interrupt to achieve better performance. But this may not work for some > > protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to > > implement various optimization for small packets stream such as TCP small > > queue and auto corking. But orphaning packets early in ndo_start_xmit() > > disable such things more or less since sk_wmem_alloc was not accurate. This > > lead extra low throughput for TCP...

...ld transmitted packets in ndo_start_xmit() currently, so any > > packet must be orphaned also there. This was used to reduce the overhead of > > tx interrupt to achieve better performance. But this may not work for some > > protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to > > implement various optimization for small packets stream such as TCP small > > queue and auto corking. But orphaning packets early in ndo_start_xmit() > > disable such things more or less since sk_wmem_alloc was not accurate. This > > lead extra low throughput for TCP...

...> We free old transmitted packets in ndo_start_xmit() currently, so any > packet must be orphaned also there. This was used to reduce the overhead of > tx interrupt to achieve better performance. But this may not work for some > protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to > implement various optimization for small packets stream such as TCP small > queue and auto corking. But orphaning packets early in ndo_start_xmit() > disable such things more or less since sk_wmem_alloc was not accurate. This > lead extra low throughput for TCP stream of small writ...

We free transmitted packets in ndo_start_xmit() in the past to get better performance in the past. One side effect is that skb_orphan() needs to be called in ndo_start_xmit() which makes sk_wmem_alloc not accurate in fact. For TCP protocol, this means several optimization could not work well such as TCP small queue and auto corking. This can lead extra low throughput of small packets stream. Thanks to the urgent descriptor support. This patch tries to solve this issue by enable the tx interrupt...

We free transmitted packets in ndo_start_xmit() in the past to get better performance in the past. One side effect is that skb_orphan() needs to be called in ndo_start_xmit() which makes sk_wmem_alloc not accurate in fact. For TCP protocol, this means several optimization could not work well such as TCP small queue and auto corking. This can lead extra low throughput of small packets stream. Thanks to the urgent descriptor support. This patch tries to solve this issue by enable the tx interrupt...

...wrote: >> > On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: >>> >> We used to limit the max pending DMAs to prevent guest from pinning too many >>> >> pages. But this could be removed since: >>> >> >>> >> - We have the sk_wmem_alloc check in both tun/macvtap to do the same work >>> >> - This max pending check were almost useless since it was one done when there's >>> >> no new buffers coming from guest. Guest can easily exceeds the limitation. >>> >> - We've already check...

...wrote: >> > On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: >>> >> We used to limit the max pending DMAs to prevent guest from pinning too many >>> >> pages. But this could be removed since: >>> >> >>> >> - We have the sk_wmem_alloc check in both tun/macvtap to do the same work >>> >> - This max pending check were almost useless since it was one done when there's >>> >> no new buffers coming from guest. Guest can easily exceeds the limitation. >>> >> - We've already check...

...{ struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; + struct vhost_poll *poll = net->poll + VHOST_NET_VQ_TX; unsigned out, in, s; int head; struct msghdr msg = { @@ -256,7 +225,7 @@ static void handle_tx(struct vhost_net *net) wmem = atomic_read(&sock->sk->sk_wmem_alloc); if (wmem >= sock->sk->sk_sndbuf) { mutex_lock(&vq->mutex); - tx_poll_start(net, sock); + vhost_poll_start(poll, sock->file); mutex_unlock(&vq->mutex); return; } @@ -265,7 +234,7 @@ static void handle_tx(struct vhost_net *net) vhost_disable_notify(&ne...

...{ struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; + struct vhost_poll *poll = net->poll + VHOST_NET_VQ_TX; unsigned out, in, s; int head; struct msghdr msg = { @@ -256,7 +225,7 @@ static void handle_tx(struct vhost_net *net) wmem = atomic_read(&sock->sk->sk_wmem_alloc); if (wmem >= sock->sk->sk_sndbuf) { mutex_lock(&vq->mutex); - tx_poll_start(net, sock); + vhost_poll_start(poll, sock->file); mutex_unlock(&vq->mutex); return; } @@ -265,7 +234,7 @@ static void handle_tx(struct vhost_net *net) vhost_disable_notify(&ne...

On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: > We used to limit the max pending DMAs to prevent guest from pinning too many > pages. But this could be removed since: > > - We have the sk_wmem_alloc check in both tun/macvtap to do the same work > - This max pending check were almost useless since it was one done when there's > no new buffers coming from guest. Guest can easily exceeds the limitation. > - We've already check upend_idx != done_idx and switch to non zerocopy th...

On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: > We used to limit the max pending DMAs to prevent guest from pinning too many > pages. But this could be removed since: > > - We have the sk_wmem_alloc check in both tun/macvtap to do the same work > - This max pending check were almost useless since it was one done when there's > no new buffers coming from guest. Guest can easily exceeds the limitation. > - We've already check upend_idx != done_idx and switch to non zerocopy th...

Hello all: We free old transmitted packets in ndo_start_xmit() currently, so any packet must be orphaned also there. This was used to reduce the overhead of tx interrupt to achieve better performance. But this may not work for some protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to implement various optimization for small packets stream such as TCP small queue and auto corking. But orphaning packets early in ndo_start_xmit() disable such things more or less since sk_wmem_alloc was not accurate. This lead extra low throughput for TCP stream of small writes. This series tri...

Hello all: We free old transmitted packets in ndo_start_xmit() currently, so any packet must be orphaned also there. This was used to reduce the overhead of tx interrupt to achieve better performance. But this may not work for some protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to implement various optimization for small packets stream such as TCP small queue and auto corking. But orphaning packets early in ndo_start_xmit() disable such things more or less since sk_wmem_alloc was not accurate. This lead extra low throughput for TCP stream of small writes. This series tri...

..._DONTWAIT, }; size_t len, total_len = 0; - int err, wmem; + int err; size_t hdr_size; struct socket *sock; struct vhost_ubuf_ref *uninitialized_var(ubufs); @@ -253,19 +221,9 @@ static void handle_tx(struct vhost_net *net) if (!sock) return; - wmem = atomic_read(&sock->sk->sk_wmem_alloc); - if (wmem >= sock->sk->sk_sndbuf) { - mutex_lock(&vq->mutex); - tx_poll_start(net, sock); - mutex_unlock(&vq->mutex); - return; - } - mutex_lock(&vq->mutex); vhost_disable_notify(&net->dev, vq); - if (wmem < sock->sk->sk_sndbuf / 2) - tx_p...

..._DONTWAIT, }; size_t len, total_len = 0; - int err, wmem; + int err; size_t hdr_size; struct socket *sock; struct vhost_ubuf_ref *uninitialized_var(ubufs); @@ -253,19 +221,9 @@ static void handle_tx(struct vhost_net *net) if (!sock) return; - wmem = atomic_read(&sock->sk->sk_wmem_alloc); - if (wmem >= sock->sk->sk_sndbuf) { - mutex_lock(&vq->mutex); - tx_poll_start(net, sock); - mutex_unlock(&vq->mutex); - return; - } - mutex_lock(&vq->mutex); vhost_disable_notify(&net->dev, vq); - if (wmem < sock->sk->sk_sndbuf / 2) - tx_p...

...l functions won't work, e.g: >> >> - Byte Queue Limit depends on tx completion nofication to work. >> - Packet Generator depends on tx completion nofication for the last >> transmitted packet to complete. >> - TCP Small Queue depends on proper accounting of sk_wmem_alloc to >> work. >> >> This series tries to solve the issue by enabling tx interrupts. To >> minize >> the performance impacts of this, several optimizations were used: >> >> - In guest side, virtqueue_enable_cb_delayed() was used to delay >> the...

...l functions won't work, e.g: >> >> - Byte Queue Limit depends on tx completion nofication to work. >> - Packet Generator depends on tx completion nofication for the last >> transmitted packet to complete. >> - TCP Small Queue depends on proper accounting of sk_wmem_alloc to >> work. >> >> This series tries to solve the issue by enabling tx interrupts. To >> minize >> the performance impacts of this, several optimizations were used: >> >> - In guest side, virtqueue_enable_cb_delayed() was used to delay >> the...

On Sat, 2014-10-11 at 15:16 +0800, Jason Wang wrote: > We free transmitted packets in ndo_start_xmit() in the past to get better > performance in the past. One side effect is that skb_orphan() needs to be > called in ndo_start_xmit() which makes sk_wmem_alloc not accurate in > fact. For TCP protocol, this means several optimization could not work well > such as TCP small queue and auto corking. This can lead extra low > throughput of small packets stream. > > Thanks to the urgent descriptor support. This patch tries to solve this > is...