similar to: [PATCH net-next 0/3] virtio-net tx napi

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Changes: v1 -> v2: - disable by default - disable unless affinity_hint_set because cache misses add up to a third higher cycle cost, e.g., in TCP_RR tests. This is not limited to the patch that enables tx completion cleaning in rx napi. - use trylock to

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Changes: v1 -> v2: - disable by default - disable unless affinity_hint_set because cache misses add up to a third higher cycle cost, e.g., in TCP_RR tests. This is not limited to the patch that enables tx completion cleaning in rx napi. - use trylock to

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Changes: v2 -> v3: - convert __netif_tx_trylock to __netif_tx_lock on tx napi poll ensure that the handler always cleans, to avoid deadlock - unconditionally clean in start_xmit avoid adding an unnecessary "if (use_napi)" branch - remove

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Changes: v2 -> v3: - convert __netif_tx_trylock to __netif_tx_lock on tx napi poll ensure that the handler always cleans, to avoid deadlock - unconditionally clean in start_xmit avoid adding an unnecessary "if (use_napi)" branch - remove

From: Willem de Bruijn <willemb at google.com> As of tx napi, device down (`ip link set dev $dev down`) hangs unless tx napi is enabled. Else napi_enable is not called, so napi_disable will spin on test_and_set_bit NAPI_STATE_SCHED. Only call napi_disable if tx napi is enabled. Fixes: 5a719c2552ca ("virtio-net: transmit napi") Reported-by: Jason Wang <jasowang at

From: Willem de Bruijn <willemb at google.com> As of tx napi, device down (`ip link set dev $dev down`) hangs unless tx napi is enabled. Else napi_enable is not called, so napi_disable will spin on test_and_set_bit NAPI_STATE_SCHED. Only call napi_disable if tx napi is enabled. Fixes: 5a719c2552ca ("virtio-net: transmit napi") Reported-by: Jason Wang <jasowang at

On newer hosts that support delayed tx interrupts, we probably don't have much to gain from orphaning packets early. Based on patch by Jason Wang. Note: this will likely degrade performance for hosts without event idx support. Various fallback options are available, including orphaning conditionally. Testing TBD. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> ---

On newer hosts that support delayed tx interrupts, we probably don't have much to gain from orphaning packets early. Based on patch by Jason Wang. Note: this will likely degrade performance for hosts without event idx support. Various fallback options are available, including orphaning conditionally. Testing TBD. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> ---

From: Willem de Bruijn <willemb at google.com> Amortize the cost of virtual interrupts by doing both rx and tx work on reception of a receive interrupt if tx napi is enabled. With VIRTIO_F_EVENT_IDX, this suppresses most explicit tx completion interrupts for bidirectional workloads. Signed-off-by: Willem de Bruijn <willemb at google.com> --- drivers/net/virtio_net.c | 22

On newer hosts that support delayed tx interrupts, we probably don't have much to gain from orphaning packets early. Based on patch by Jason Wang. Note: this might degrade performance for hosts without event idx support. Should be addressed by the next patch. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 137

On newer hosts that support delayed tx interrupts, we probably don't have much to gain from orphaning packets early. Based on patch by Jason Wang. Note: this might degrade performance for hosts without event idx support. Should be addressed by the next patch. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 137

According to David, proper accounting and queueing (at all levels, not just TCP sockets) is more important than trying to skim a bunch of cycles by avoiding TX interrupts. Having an event to free the SKB is absolutely essential for the stack to operate correctly. This series tries to enable tx interrupt for virtio-net. The idea is simple: enable tx interrupt and schedule a tx napi to free old

According to David, proper accounting and queueing (at all levels, not just TCP sockets) is more important than trying to skim a bunch of cycles by avoiding TX interrupts. Having an event to free the SKB is absolutely essential for the stack to operate correctly. This series tries to enable tx interrupt for virtio-net. The idea is simple: enable tx interrupt and schedule a tx napi to free old

On Mon, Dec 01, 2014 at 06:17:04PM +0800, Jason Wang wrote: > On newer hosts that support delayed tx interrupts, > we probably don't have much to gain from orphaning > packets early. > > Note: this might degrade performance for > hosts without event idx support. > Should be addressed by the next patch. > > Cc: Rusty Russell <rusty at rustcorp.com.au> > Cc:

On Mon, Dec 01, 2014 at 06:17:04PM +0800, Jason Wang wrote: > On newer hosts that support delayed tx interrupts, > we probably don't have much to gain from orphaning > packets early. > > Note: this might degrade performance for > hosts without event idx support. > Should be addressed by the next patch. > > Cc: Rusty Russell <rusty at rustcorp.com.au> > Cc:

On 10/15/2014 06:18 PM, Michael S. Tsirkin wrote: > On Wed, Oct 15, 2014 at 03:25:29PM +0800, Jason Wang wrote: >> > Orphan skb in ndo_start_xmit() breaks socket accounting and packet >> > queuing. This in fact breaks lots of things such as pktgen and several >> > TCP optimizations. And also make BQL can't be implemented for >> > virtio-net. >> >

On 10/15/2014 06:18 PM, Michael S. Tsirkin wrote: > On Wed, Oct 15, 2014 at 03:25:29PM +0800, Jason Wang wrote: >> > Orphan skb in ndo_start_xmit() breaks socket accounting and packet >> > queuing. This in fact breaks lots of things such as pktgen and several >> > TCP optimizations. And also make BQL can't be implemented for >> > virtio-net. >> >

Orphan skb in ndo_start_xmit() breaks socket accounting and packet queuing. This in fact breaks lots of things such as pktgen and several TCP optimizations. And also make BQL can't be implemented for virtio-net. This patch tries to solve this issue by enabling tx interrupt. To avoid introducing extra spinlocks, a tx napi was scheduled to free those packets. More tx interrupt mitigation

Orphan skb in ndo_start_xmit() breaks socket accounting and packet queuing. This in fact breaks lots of things such as pktgen and several TCP optimizations. And also make BQL can't be implemented for virtio-net. This patch tries to solve this issue by enabling tx interrupt. To avoid introducing extra spinlocks, a tx napi was scheduled to free those packets. More tx interrupt mitigation

Hi all: This series is an update version of multiqueue virtio-net driver based on Krishna Kumar's work to let virtio-net use multiple rx/tx queues to do the packets reception and transmission. Please review and comments. A protype implementation of qemu-kvm support could by found in git://github.com/jasowang/qemu-kvm-mq.git. To start a guest with two queues, you could specify the queues