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Bug #3089

vtnet(4) - disable TCP checksum offload by default

Added by jlane 28 days ago. Updated 27 days ago.

Status:
In Progress
Priority:
Normal
Assignee:
Category:
Driver
Target version:
Start date:
10/21/2017
Due date:
% Done:

0%


Description

The existing TCP checksum offset for this driver causes ~95% retransmit rates for TCP IPv6 packets. This makes the driver effectively useless in its current state on IPv6 networks. Fixing the checksum offload code is beyond my expertise at this time, so we should at least disable the offload by default.

Patch for sys/dev/virtual/virtio/net/if_vtnet.c:

166c166
< static int vtnet_csum_disable = 0;
---
> static int vtnet_csum_disable = 1; //broken for IPv6, disable by default


Related issues

Related to Bug #3090: VirtIO/vtnet: very poor IPv6 receiving performance (~100x slower) In Progress 10/23/2017

History

#1 Updated by vadaszi 27 days ago

I cherry-picked 849f77c77acc4d5041fa638b364cb6a296a8051b (from a few days ago, which is also just disabling checksum offload) from git master to the DragonFly_RELEASE_5_0 branch.

#2 Updated by vadaszi 27 days ago

  • Status changed from New to In Progress
  • Assignee set to vadaszi

#3 Updated by liweitianux 27 days ago

  • Related to Bug #3090: VirtIO/vtnet: very poor IPv6 receiving performance (~100x slower) added

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