virtio-net: Set dev->needed_headroom for virtio-net device when it has the feature VIRTIO_F_ANY_LAYOUT
Subsystems (3)
PATCH 1/1 virtio-net: Set dev->needed_headroom for virtio-net device when it has the feature VIRTIO_F_ANY_LAYOUT
This is a small supplement for commit e7428e95a06fb516fac1308bd0e176e27c0b9287("virtio-net: put virtio-net header inline with data"). TCP packages have enough room to put virtio-net header in, but UDP packages do not. By setting dev->needed_headroom for virtio-net device, UDP packages could have enough room.
For UDP packages, sk_buff is alloced in fun __ip_append_data. The size is "alloclen + hh_len + 15", and "hh_len = LL_RESERVED_SPACE(rt->dst.dev);". The Macro is defined as follows:
#define LL_RESERVED_SPACE(dev) \
((((dev)->hard_header_len+(dev)->needed_headroom)\
&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)By default, for UDP packages, after skb is allocated, only 16 bytes reserved. And 2 bytes remained after mac header is set. That is not enough to put virtio-net header in. If we set dev->needed_headroom to 12 or 10 (according to mergeable_rx_bufs is on or off ), more room can be reserved. Then there is enough room for UDP packages to put the header in.
test result list as below:
guest and host: suse11sp3, netperf, intel 2.4GHz
+-------+---------+---------+---------+---------+ | | old | | new | | +-------+---------+---------+---------+---------+ | UDP | Gbit/s | PPs | Gbit/s | PPs | | 64 | 0.573 | 692232 | 0.614 | 742420 | | 256 | 1.6 | 686860 | 1.71 | 733331 | | 512 | 2.92 | 674576 | 3.07 | 710446 | | 1024 | 4.99 | 598977 | 5.17 | 620821 | | 1460 | 5.68 | 483757 | 7.16 | 610519 | +-------+---------+---------+---------+---------+
--- drivers/net/virtio_net.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)
drivers/net/virtio_net.c +7 -0
@@ -1724,6 +1724,13 @@ static int virtnet_probe(struct virtio_device *vdev)if (virtio_has_feature (vdev,VIRTIO_NET_F_CTRL_VQ )) vi->has_cvq = true; +if (vi->any_header_sg) { +if (vi->mergeable_rx_bufs) + dev->needed_headroom =sizeof (struct virtio_net_hdr_mrg_rxbuf ); +else + dev->needed_headroom =sizeof (struct virtio_net_hdr ); + } +/* Use single tx/rx queue pair as default */ vi->curr_queue_pairs =1 ; vi->max_queue_pairs = max_queue_pairs;
Signature · 1 line
1.7.1
Quoted 46 lines · Zhangjie (HZ)
This is a small supplement for commit
e7428e95a06fb516fac1308bd0e176e27c0b9287("virtio-net: put virtio-net header inline with data"). TCP packages have enough room to put virtio-net header in, but UDP packages do not. By settingdev->needed_headroomfor virtio-net device, UDP packages could have enough room.For UDP packages,
sk_buffis alloced in fun__ip_append_data. The size is "alloclen +hh_len+ 15", and "hh_len=LL_RESERVED_SPACE(rt->dst.dev);".
The Macro is defined as follows:#define LL_RESERVED_SPACE(dev) \ ((((dev)->hard_header_len+(dev)->needed_headroom)\ &~(HH_DATA_MOD - 1)) + HH_DATA_MOD)By default, for UDP packages, after skb is allocated, only 16 bytes reserved. And 2 bytes remained after mac header is set. That is not enough to put virtio-net header in. If we set
dev->needed_headroomto 12 or 10 (according tomergeable_rx_bufsis on or off ), more room can be reserved. Then there is enough room for UDP packages to put the header in.test result list as below:
guest and host: suse11sp3, netperf, intel 2.4GHz+-------+---------+---------+---------+---------+ | | old | | new | | +-------+---------+---------+---------+---------+ | UDP | Gbit/s | PPs | Gbit/s | PPs | | 64 | 0.573 | 692232 | 0.614 | 742420 | | 256 | 1.6 | 686860 | 1.71 | 733331 | | 512 | 2.92 | 674576 | 3.07 | 710446 | | 1024 | 4.99 | 598977 | 5.17 | 620821 | | 1460 | 5.68 | 483757 | 7.16 | 610519 | +-------+---------+---------+---------+---------+Signed-off-by ZhangJie <[email protected]>--- drivers/net/virtio_net.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)drivers/net/virtio_net.c +0
-0@@ -1724,6 +1724,13 @@ static int virtnet_probe(struct virtio_device *vdev)if (virtio_has_feature (vdev,VIRTIO_NET_F_CTRL_VQ )) vi->has_cvq = true;
drivers/net/virtio_net.c static int virtnet_probe(struct virtio_device *vdev) · line 1735
Quoted 10 lines
drivers/net/virtio_net.c +7
-0+if (vi->any_header_sg) { +if (vi->mergeable_rx_bufs) + dev->needed_headroom =sizeof (struct virtio_net_hdr_mrg_rxbuf ); +else + dev->needed_headroom =sizeof (struct virtio_net_hdr ); + } +
Looks like your mailer corrupted the patch. You can see what it looks like here:
http://patchwork.ozlabs.org/patch/343388/
-vlad
Quoted 3 lines
drivers/net/virtio_net.c +0
-0/* Use single tx/rx queue pair as default */ vi->curr_queue_pairs = 1; vi->max_queue_pairs = max_queue_pairs;
Michael S. Tsirkin
maintainerQuoted 33 lines · Zhangjie (HZ)
This is a small supplement for commit
e7428e95a06fb516fac1308bd0e176e27c0b9287("virtio-net: put virtio-net header inline with data"). TCP packages have enough room to put virtio-net header in, but UDP packages do not. By settingdev->needed_headroomfor virtio-net device, UDP packages could have enough room.For UDP packages,
sk_buffis alloced in fun__ip_append_data. The size is "alloclen +hh_len+ 15", and "hh_len=LL_RESERVED_SPACE(rt->dst.dev);". The Macro is defined as follows:#define LL_RESERVED_SPACE(dev) \ ((((dev)->hard_header_len+(dev)->needed_headroom)\ &~(HH_DATA_MOD - 1)) + HH_DATA_MOD)By default, for UDP packages, after skb is allocated, only 16 bytes reserved. And 2 bytes remained after mac header is set. That is not enough to put virtio-net header in. If we set
dev->needed_headroomto 12 or 10 (according tomergeable_rx_bufsis on or off ), more room can be reserved. Then there is enough room for UDP packages to put the header in.test result list as below:
guest and host: suse11sp3, netperf, intel 2.4GHz+-------+---------+---------+---------+---------+ | | old | | new | | +-------+---------+---------+---------+---------+ | UDP | Gbit/s | PPs | Gbit/s | PPs | | 64 | 0.573 | 692232 | 0.614 | 742420 | | 256 | 1.6 | 686860 | 1.71 | 733331 | | 512 | 2.92 | 674576 | 3.07 | 710446 | | 1024 | 4.99 | 598977 | 5.17 | 620821 | | 1460 | 5.68 | 483757 | 7.16 | 610519 | +-------+---------+---------+---------+---------+
Quoted 1 line
Signed-off-by ZhangJie <[email protected]>
Thanks, results look nice.
However - please check Documentation/email-clients.txt and set up your client to send well-formed patches, then pls repost.
You also want to Cc all relevant people and lists: use
the get_maintainer.pl script to get the list.
Also, you need to Cc Dave Miller if you want him to apply your patch.
Quoted 27 lines
--- drivers/net/virtio_net.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)drivers/net/virtio_net.c +7
-0@@ -1724,6 +1724,13 @@ static int virtnet_probe(struct virtio_device *vdev)if (virtio_has_feature (vdev,VIRTIO_NET_F_CTRL_VQ )) vi->has_cvq = true; +if (vi->any_header_sg) { +if (vi->mergeable_rx_bufs) + dev->needed_headroom =sizeof (struct virtio_net_hdr_mrg_rxbuf ); +else + dev->needed_headroom =sizeof (struct virtio_net_hdr ); + } +/* Use single tx/rx queue pair as default */ drivers/net/virtio_net.c +0
-0vi->curr_queue_pairs =1 ; vi->max_queue_pairs = max_queue_pairs;Signature · 1 line
1.7.1