similar to: [PATCH RFC v4 net-next 0/5] virtio_net: enabling tx interrupts

Hi: This is a new version of trying to enable tx interrupts for virtio-net. We used to try to avoid tx interrupts and orphan packets before transmission for virtio-net. This breaks socket accounting and can lead serveral other side effects e.g: - Several other functions which depends on socket accounting can not work correctly (e.g TCP Small Queue) - No tx completion which make BQL or

Hi: This is a new version of trying to enable tx interrupts for virtio-net. We used to try to avoid tx interrupts and orphan packets before transmission for virtio-net. This breaks socket accounting and can lead serveral other side effects e.g: - Several other functions which depends on socket accounting can not work correctly (e.g TCP Small Queue) - No tx completion which make BQL or

Hi: This is a new version of trying to enable tx interrupts for virtio-net. We used to try to avoid tx interrupts and orphan packets before transmission for virtio-net. This breaks socket accounting and can lead serveral other side effects e.g: - Several other functions which depends on socket accounting can not work correctly (e.g TCP Small Queue) - No tx completion which make BQL or packet

Hi: This is a new version of trying to enable tx interrupts for virtio-net. We used to try to avoid tx interrupts and orphan packets before transmission for virtio-net. This breaks socket accounting and can lead serveral other side effects e.g: - Several other functions which depends on socket accounting can not work correctly (e.g TCP Small Queue) - No tx completion which make BQL or packet

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

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

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> ---

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

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

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

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. >> >

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Based on previous patchsets by Jason Wang: [RFC V7 PATCH 0/7] enable tx interrupts for virtio-net http://lkml.iu.edu/hypermail/linux/kernel/1505.3/00245.html Changes: RFC -> v1: - dropped vhost interrupt moderation patch: not needed and likely expensive at light

From: Willem de Bruijn <willemb at google.com> Add napi for virtio-net transmit completion processing. Based on previous patchsets by Jason Wang: [RFC V7 PATCH 0/7] enable tx interrupts for virtio-net http://lkml.iu.edu/hypermail/linux/kernel/1505.3/00245.html Changes: RFC -> v1: - dropped vhost interrupt moderation patch: not needed and likely expensive at light