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Re: [Qemu-devel] [ RFC Patch v5 0/2] Support Receive-Segment-Offload(RSC
Re: [Qemu-devel] [ RFC Patch v5 0/2] Support Receive-Segment-Offload(RSC) for WHQL
Tue, 24 May 2016 16:03:04 +0800
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2
On 2016年05月24日 04:14, address@hidden wrote:
From: Wei Xu <address@hidden>
Changes in V5:
- Passed all IPv4/6 test cases
- Add new fields in 'virtio_net_hdr'
- Set 'gso_type' & 'coalesced packets' in new field.
- Bypass all 'tcp option' packet
- Bypass all 'pure ack' packet
- Bypass all 'duplicate ack' packet
- Change 'guest_rsc' feature bit to 'false' by default
- Feedbacks from v4, typo, etc.
Patch does not apply on master ...
There is still a few pending issues about the feature bit, and need to be
discussed with windows driver maintainer, so linux guests with this patch
won't work at current, haven't figure it out yet, but i'm guessing it's
caused by the 'gso_type' is set to 'VIRTIO_NET_HDR_GSO_TCPV4/6',
will fix it after get the final solution, the below test steps and
performance data is based on v4.
Can we split the patches into smaller ones to make review or merging
easier? E.g can we send the patches without any feature negotiation and
vnet header extension?
We can focus on the coalescing (maybe ipv4) without any guest
involvement in this series. In this way, the issues were limited and can
be converged soon. After this has been merged, we can add patches that
co-operate with guests on top (since it needs agreement on virtio
specs). Does this sounds a good plan?
Another suggestion from Jason is to adjust part of the code to make it
more readable, since there maybe still few change about the flowchart
in the future, such as timestamp, duplicate ack, so i'd like to delay it
Changes in V4:
- Add new host feature bit
- Replace using fixed header lenght with dynamic header lenght in VirtIONet
- Change ip/ip6 header union in NetRscUnit to void* pointer
- Add macro prefix, adjust code indent, etc.
Changes in V3:
- Removed big param list, replace it with 'NetRscUnit'
- Different virtio header size
- Modify callback function to direct call.
- Needn't check the failure of g_malloc()
- Other code format adjustment, macro naming, etc
Changes in V2:
- Add detailed commit log
This patch is to support WHQL test for Windows guest, while this feature also
benifits other guest works as a kernel 'gro' like feature with userspace
Both IPv4 and IPv6 are supported, though performance with userspace virtio
is slow than vhost-net, there is about 1.5x to 2x performance improvement to
userspace virtio, this is done by turning this feature on and disable
'tso/gso/gro' on corresponding tap interface and guest interface, while get
less improment with all these feature on.
Linux guest performance data(Netperf):
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.2.101
() port 0 AF_INET : nodelay
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 64 6.00 1221.20
87380 16384 64 6.00 1260.30
87380 16384 128 6.00 1978.51
87380 16384 128 6.00 2286.05
87380 16384 256 6.00 2677.94
87380 16384 256 6.00 4615.42
87380 16384 512 6.00 2956.54
87380 16384 512 6.00 5356.39
87380 16384 1024 6.00 2798.17
87380 16384 1024 6.00 4943.30
87380 16384 2048 6.00 2681.09
87380 16384 2048 6.00 4835.81
87380 16384 4096 6.00 3390.14
87380 16384 4096 6.00 5391.54
87380 16384 8092 6.00 3008.27
87380 16384 8092 6.00 5381.68
87380 16384 10240 6.00 2999.89
87380 16384 10240 6.00 5393.11
Although this feature is mainly used for window guest, i used linux guest to
help test the feature, to make things simple, i used 3 steps to test the patch
as i moved on.
1. With a tcp socket client/server pair running on 2 linux guest, thus i can
the traffic and debugging the code as i want.
2. Netperf on linux guest test the throughput.
3. WHQL test with 2 Windows guests.
Wei Xu (2):
virtio-net rsc: support coalescing ipv4 tcp traffic
virtio-net rsc: support coalescing ipv6 tcp traffic
hw/net/virtio-net.c | 623 +++++++++++++++++++++++++++-
include/hw/virtio/virtio-net.h | 2 +
include/hw/virtio/virtio.h | 75 ++++
include/standard-headers/linux/virtio_net.h | 2 +
4 files changed, 699 insertions(+), 3 deletions(-)