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...tadata information through XDP_REDIRECT to another driver. - XDP does not support checksum offload right now. So simply disable guest csum if possible in this the case of XDP. Fixes: 3f93522ffab2d ("virtio-net: switch off offloads on demand if possible on XDP set") Reported-by: Jesper Dangaard Brouer <brouer at redhat.com> Cc: Jesper Dangaard Brouer <brouer at redhat.com> Cc: Pavel Popa <pashinho1990 at gmail.com> Cc: David Ahern <dsahern at gmail.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 8 ++------ 1 file chang...

...tadata information through XDP_REDIRECT to another driver. - XDP does not support checksum offload right now. So simply disable guest csum if possible in this the case of XDP. Fixes: 3f93522ffab2d ("virtio-net: switch off offloads on demand if possible on XDP set") Reported-by: Jesper Dangaard Brouer <brouer at redhat.com> Cc: Jesper Dangaard Brouer <brouer at redhat.com> Cc: Pavel Popa <pashinho1990 at gmail.com> Cc: David Ahern <dsahern at gmail.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 8 ++------ 1 file chang...

On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 11:19:03 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> This series tries to re-enable XDP_REDIRECT for mergeable buffer which >> was removed since commit 7324f5399b06 ("virtio_net: disable >> XDP_REDIRECT in receive...

On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 11:19:03 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> This series tries to re-enable XDP_REDIRECT for mergeable buffer which >> was removed since commit 7324f5399b06 ("virtio_net: disable >> XDP_REDIRECT in receive...

On 2018?03?01? 18:35, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 17:23:37 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: >>> On Thu, 1 Mar 2018 11:19:03 +0800 >>> Jason Wang <jasowang at redhat.com> wrote: >>>...

On 2018?03?01? 18:35, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 17:23:37 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: >>> On Thu, 1 Mar 2018 11:19:03 +0800 >>> Jason Wang <jasowang at redhat.com> wrote: >>>...

....data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve space for vnet header in this case. Cc: Jesper Dangaard Brouer <brouer at redhat.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 11f722460513..98dd75b665a5 100644 --- a/driv...

....data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve space for vnet header in this case. Cc: Jesper Dangaard Brouer <brouer at redhat.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 11f722460513..98dd75b665a5 100644 --- a/driv...

...to net_device open/close functions. Driver hook points for xdp_rxq_info: * reg : virtnet_open * unreg: virtnet_close Cc: "Michael S. Tsirkin" <mst at redhat.com> Cc: Jason Wang <jasowang at redhat.com> Cc: virtualization at lists.linux-foundation.org Signed-off-by: Jesper Dangaard Brouer <brouer at redhat.com> --- drivers/net/virtio_net.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 6fb7b658a6cc..6d45d687ec6a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_ne...

On Thu, 1 Mar 2018 21:15:36 +0800 Jason Wang <jasowang at redhat.com> wrote: > On 2018?03?01? 18:35, Jesper Dangaard Brouer wrote: > > On Thu, 1 Mar 2018 17:23:37 +0800 > > Jason Wang <jasowang at redhat.com> wrote: > > > >> On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: > >>> On Thu, 1 Mar 2018 11:19:03 +0800 > >>> Jason Wang <jasowang at redh...

On 2020/5/6 ??4:21, Jesper Dangaard Brouer wrote: > On Wed, 6 May 2020 14:16:32 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> We tried to reserve space for vnet header before >> xdp.data_hard_start. But this is useless since the packet could be >> modified by XDP which may invalidate the in...

On 2020/5/6 ??4:21, Jesper Dangaard Brouer wrote: > On Wed, 6 May 2020 14:16:32 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> We tried to reserve space for vnet header before >> xdp.data_hard_start. But this is useless since the packet could be >> modified by XDP which may invalidate the in...

...out the patch: 24.4 Gbits/sec > > netperf (TCP_RR): > * With the patch: 47963.25 trans/s, 20.71us mean latency > * Without the patch: 45796.70 trans/s, 21.68us mean latency > > Signed-off-by: Tonghao Zhang <zhangtonghao at didichuxing.com> -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer

On Wed, May 06, 2020 at 02:16:33PM +0800, Jason Wang wrote: > We should not exclude headroom and tailroom when XDP is set. So this > patch fixes this by initializing the truesize from PAGE_SIZE when XDP > is set. > > Cc: Jesper Dangaard Brouer <brouer at redhat.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> Seems too aggressive, we do not use up the whole page for the size. > --- > drivers/net/virtio_net.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/...

On Wed, May 06, 2020 at 02:16:33PM +0800, Jason Wang wrote: > We should not exclude headroom and tailroom when XDP is set. So this > patch fixes this by initializing the truesize from PAGE_SIZE when XDP > is set. > > Cc: Jesper Dangaard Brouer <brouer at redhat.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> Seems too aggressive, we do not use up the whole page for the size. > --- > drivers/net/virtio_net.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/...

...or struct > skb_shared_info which breaks XDP assumption. Other complaints are, the > complex linearize logic and EWMA estimation may increase the > possibility of linearizing. This patch also have the intermixing issues, I mentioned for patch 2/2. On Thu, 1 Mar 2018 09:02:06 +0100 Jesper Dangaard Brouer <brouer at redhat.com> wrote: > 1. XDP generic is not feature complete, e.g. cpumap will drop these > packets. It might not be possible to implement some features, think > of (AF_XDP) zero-copy. > > 2. This can easily cause out-of-order packets. > > 3. It...

So for mergeable bufs, we use ewma machinery to guess the correct buffer size. If we don't guess correctly, XDP has to do aggressive copies. Problem is, xdp paths do not update the ewma at all, except sometimes with XDP_PASS. So whatever we happen to have before we attach XDP, will mostly stay around. The fix is probably to update ewma unconditionally. -- MST

So for mergeable bufs, we use ewma machinery to guess the correct buffer size. If we don't guess correctly, XDP has to do aggressive copies. Problem is, xdp paths do not update the ewma at all, except sometimes with XDP_PASS. So whatever we happen to have before we attach XDP, will mostly stay around. The fix is probably to update ewma unconditionally. -- MST

...V3: - bugfix, also setup xdp.rxq in receive_mergeable() - Tested bpf-sample prog inside guest on a virtio_net device Cc: "Michael S. Tsirkin" <mst at redhat.com> Cc: Jason Wang <jasowang at redhat.com> Cc: virtualization at lists.linux-foundation.org Signed-off-by: Jesper Dangaard Brouer <brouer at redhat.com> --- drivers/net/virtio_net.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 6fb7b658a6cc..ed8299343728 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_...

...give a strange user experience given point #1. > + */ > if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) { > - int offset = buf - page_address(page) + header_offset; > - unsigned int tlen = len + vi->hdr_len; > - u16 num_buf = 1; -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer