Messages in this thread | | | Subject | Re: [PATCH net] macvtap: unbreak receiving of gro skb with frag list | From | Jason Wang <> | Date | Tue, 27 Oct 2015 10:58:25 +0800 |
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On 10/26/2015 04:30 PM, Michael S. Tsirkin wrote: > On Mon, Oct 26, 2015 at 02:53:38PM +0800, Jason Wang wrote: >> >> On 10/26/2015 02:09 PM, Michael S. Tsirkin wrote: >>> On Mon, Oct 26, 2015 at 11:15:57AM +0800, Jason Wang wrote: >>>> On 10/23/2015 09:37 PM, Michael S. Tsirkin wrote: >>>>> On Fri, Oct 23, 2015 at 12:57:05AM -0400, Jason Wang wrote: >>>>>> We don't have fraglist support in TAP_FEATURES. This will lead >>>>>> software segmentation of gro skb with frag list. Fixes by having >>>>>> frag list support in TAP_FEATURES. >>>>>> >>>>>> With this patch single session of netperf receiving were restored from >>>>>> about 5Gb/s to about 12Gb/s on mlx4. >>>>>> >>>>>> Fixes a567dd6252 ("macvtap: simplify usage of tap_features") >>>>>> Cc: Vlad Yasevich <vyasevic@redhat.com> >>>>>> Cc: Michael S. Tsirkin <mst@redhat.com> >>>>>> Signed-off-by: Jason Wang <jasowang@redhat.com> >>>>> Thanks! >>>>> Does this mean we should look at re-adding NETIF_F_FRAGLIST >>>>> to virtio-net as well? >>>> Not sure I get the point, but probably not. This is for receiving and >>>> skb_copy_datagram_iter() can deal with frag list. >>> Point is: >>> - bridge within guest >>> - assigned device creating gro skbs with frag list bridged to virtio >> I see, but this problem looks not specific to virtio. Most cards does >> not support frag list. > These will be slower when used with a bridge then, won't they?
For forwarding, not sure. GRO has latency and cpu overhead anyway.
Anyway I can try to add the support for this.
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