Re: Hardware checksums on bge(4) interfaces

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        Hello.  Typically, I enable those flags in the ifconfig.xxx files for
those interfaces that want them.  In the case of bge(4), I've found some
revisions of the chip that don't do tcp checksumming corectly.
So, for the bge chips I use, I typically only use ip4csum and udp4csum.
There are probably versions of the chip that I have that work right, but
since the failure mode is odd and hard to detect, I play it conservatively.
        For the most part, unless your server is heavily loaded, I believe the
difference in performance between using hardware and software checksumming
is quite negligible.

I'd be interested in someone who has more knowledge of such things speaking
up.
-Brian
On Sep 13, 12:34pm, Chris Ross wrote:
} Subject: Hardware checksums on bge(4) interfaces
} 
}    Just a question.  Is there any reason *not* to use the various pieces 
} of hardware checksumming that are shown as available on my bge(4) 
} interfaces?  Each of them show bidirectional IP, TCP, and UDP checksum 
} capabilities.  But, they're not enabled by default.  I would've expected 
} that they'd just *always* be valuable, but they're not automatically 
} enabled, so I was wondering what the reasons would be to turn them on, 
} to leave them turned off, etc.
} 
}    Sorry if this should be a tech-net question, but it is really meant 
} to be pretty inspecific and open.  Thanks.
} 
}                                                          - Chris
} 
} --
} Chris Ross
} 
>-- End of excerpt from Chris Ross