if_bridge turns off checksum offload of members?
thompsa at FreeBSD.org
Tue Jul 1 01:24:10 UTC 2008
On Mon, Jun 30, 2008 at 07:16:29PM +0900, Pyun YongHyeon wrote:
> On Mon, Jun 30, 2008 at 12:11:40PM +0300, Stefan Lambrev wrote:
> > Greetings,
> > I just noticed, that when I add em network card to bridge the checksum
> > offload is turned off.
> > I even put in my rc.conf:
> > ifconfig_em0="rxcsum up"
> > ifconfig_em1="rxcsum up"
> > but after reboot both em0 and em1 have this feature disabled.
> > Is this expected behavior? Should I care about csum in bridge mode?
> > I noticed that enabling checksum offload manually improve things little btw.
> AFAIK this is intended one, bridge(4) turns off Tx side checksum
> offload by default. I think disabling Tx checksum offload is
> required as not all members of a bridge may be able to do checksum
> offload. The same is true for TSO but it seems that bridge(4)
> doesn't disable it.
> If all members of bridge have the same hardware capability I think
> bridge(4) may not need to disable Tx side hardware assistance. I
> guess bridge(4) can scan every interface capabilities in a member
> and can decide what hardware assistance can be activated instead of
> blindly turning off Tx side hardware assistance.
This patch should do that, are you able to test it Stefan?
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