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| author |   Haiyang Zhang <haiyangz@microsoft.com> | 2017-08-21 19:22:40 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-08-22 14:08:12 -0700 |
| commit | 3b0c34580b7ab9bb1d4a375e427af6a75ca45821 (patch) | |
| tree | edaaeedb401570d404c71ec1117a6e4bb85f5160 /Documentation | |
| parent | hv_netvsc: Add ethtool handler to set and get UDP hash levels (diff) | |
| download | linux-dev-3b0c34580b7ab9bb1d4a375e427af6a75ca45821.tar.xz linux-dev-3b0c34580b7ab9bb1d4a375e427af6a75ca45821.zip | |
hv_netvsc: Update netvsc Document for UDP hash level setting
Update Documentation/networking/netvsc.txt for UDP hash level setting
and related info.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/netvsc.txt | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/Documentation/networking/netvsc.txt b/Documentation/networking/netvsc.txt index 4ddb4e4b0426..fa8d86356791 100644 --- a/Documentation/networking/netvsc.txt +++ b/Documentation/networking/netvsc.txt @@ -21,11 +21,23 @@ Features -------------------- Hyper-V supports receive side scaling. For TCP, packets are distributed among available queues based on IP address and port - number. Current versions of Hyper-V host, only distribute UDP - packets based on the IP source and destination address. - The port number is not used as part of the hash value for UDP. - Fragmented IP packets are not distributed between queues; - all fragmented packets arrive on the first channel. + number. + + For UDP, we can switch UDP hash level between L3 and L4 by ethtool + command. UDP over IPv4 and v6 can be set differently. The default + hash level is L4. We currently only allow switching TX hash level + from within the guests. + + On Azure, fragmented UDP packets have high loss rate with L4 + hashing. Using L3 hashing is recommended in this case. + + For example, for UDP over IPv4 on eth0: + To include UDP port numbers in hasing: + ethtool -N eth0 rx-flow-hash udp4 sdfn + To exclude UDP port numbers in hasing: + ethtool -N eth0 rx-flow-hash udp4 sd + To show UDP hash level: + ethtool -n eth0 rx-flow-hash udp4 Generic Receive Offload, aka GRO -------------------------------- |