On Sun, Feb 05, 2017 at 05:36:34PM -0500, David Miller wrote: > From: John Fastabend <john.fastab...@gmail.com> > Date: Thu, 02 Feb 2017 19:14:05 -0800 > > > This series adds adjust head support for virtio. The following is my > > test setup. I use qemu + virtio as follows, > > > > ./x86_64-softmmu/qemu-system-x86_64 \ > > -hda /var/lib/libvirt/images/Fedora-test0.img \ > > -m 4096 -enable-kvm -smp 2 -netdev tap,id=hn0,queues=4,vhost=on \ > > -device > > virtio-net-pci,netdev=hn0,mq=on,guest_tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off,vectors=9 > > > > In order to use XDP with virtio until LRO is supported TSO must be > > turned off in the host. The important fields in the above command line > > are the following, > > > > guest_tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off > > > > Also note it is possible to conusme more queues than can be supported > > because when XDP is enabled for retransmit XDP attempts to use a queue > > per cpu. My standard queue count is 'queues=4'. > > > > After loading the VM I run the relevant XDP test programs in, > > > > ./sammples/bpf > > > > For this series I tested xdp1, xdp2, and xdp_tx_iptunnel. I usually test > > with iperf (-d option to get bidirectional traffic), ping, and pktgen. > > I also have a modified xdp1 that returns XDP_PASS on any packet to ensure > > the normal traffic path to the stack continues to work with XDP loaded. > > > > It would be great to automate this soon. At the moment I do it by hand > > which is starting to get tedious. > > > > v2: original series dropped trace points after merge. > > Michael, I just want to apply this right now. > > I don't think haggling over whether to allocate the adjust_head area > unconditionally or not is a blocker for this series going in. That > can be addressed trivially in a follow-on patch.
FYI it would just mean we revert most of this patchset except patches 2 and 3 though. > We want these new reset paths tested as much as possible and each day > we delay this series is detrimental towards that goal. > > Thanks. Well the point is to avoid resets completely, at the cost of extra 256 bytes for packets > 128 bytes on ppc (64k pages) only. Found a volunteer so I hope to have this idea tested on ppc Tuesday. And really all we need to know is confirm whether this: -#define MERGEABLE_BUFFER_MIN_ALIGN_SHIFT ((PAGE_SHIFT + 1) / 2) +#define MERGEABLE_BUFFER_MIN_ALIGN_SHIFT (PAGE_SHIFT / 2 + 1) affects performance in a measureable way. So I would rather wait another day. But the patches themselves look correct, from that POV. Acked-by: Michael S. Tsirkin <m...@redhat.com> but I would prefer that you waited another day for a Tested-by from me too. -- MST
