search for: dev_kfree_skb_ani

From: Of Michael S. Tsirkin > On Wed, Oct 15, 2014 at 03:25:27PM +0800, Jason Wang wrote: > > Accumulate the sent packets and sent bytes in local variables and perform a > > single u64_stats_update_begin/end() after. > > > > Cc: Rusty Russell <rusty at rustcorp.com.au> > > Cc: Michael S. Tsirkin <mst at redhat.com> > > Signed-off-by: Jason Wang

From: Of Michael S. Tsirkin > On Wed, Oct 15, 2014 at 03:25:27PM +0800, Jason Wang wrote: > > Accumulate the sent packets and sent bytes in local variables and perform a > > single u64_stats_update_begin/end() after. > > > > Cc: Rusty Russell <rusty at rustcorp.com.au> > > Cc: Michael S. Tsirkin <mst at redhat.com> > > Signed-off-by: Jason Wang

From: Michael S. Tsirkin > On Wed, Oct 15, 2014 at 09:49:01AM +0000, David Laight wrote: > > From: Of Michael S. Tsirkin > > > On Wed, Oct 15, 2014 at 03:25:27PM +0800, Jason Wang wrote: > > > > Accumulate the sent packets and sent bytes in local variables and perform a > > > > single u64_stats_update_begin/end() after. > > > > > > >

From: Michael S. Tsirkin > On Wed, Oct 15, 2014 at 09:49:01AM +0000, David Laight wrote: > > From: Of Michael S. Tsirkin > > > On Wed, Oct 15, 2014 at 03:25:27PM +0800, Jason Wang wrote: > > > > Accumulate the sent packets and sent bytes in local variables and perform a > > > > single u64_stats_update_begin/end() after. > > > > > > >

Accumulate the sent packets and sent bytes in local variables and perform a single u64_stats_update_begin/end() after. Cc: Rusty Russell <rusty at rustcorp.com.au> Cc: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git

Accumulate the sent packets and sent bytes in local variables and perform a single u64_stats_update_begin/end() after. Cc: Rusty Russell <rusty at rustcorp.com.au> Cc: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git

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

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. >> >

On Wed, Oct 15, 2014 at 09:49:01AM +0000, David Laight wrote: > From: Of Michael S. Tsirkin > > On Wed, Oct 15, 2014 at 03:25:27PM +0800, Jason Wang wrote: > > > Accumulate the sent packets and sent bytes in local variables and perform a > > > single u64_stats_update_begin/end() after. > > > > > > Cc: Rusty Russell <rusty at rustcorp.com.au> >

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> ---

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

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.

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.

On Wed, Oct 15, 2014 at 06:25:25PM +0800, Jason Wang wrote: > 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.