accept filters and zero copy sockets

Kris Kennaway kris at
Sat Oct 20 00:32:11 PDT 2007

Vlad GALU wrote:
> On 10/19/07, Jonathan Noack <noackjr at> wrote:
>> I'm in the process of upgrading my web/database/nfs/jack-of-all-trades box
>> from 6.2 to RELENG_7.  I figured now would be a good time to clean up my
>> kernel config files.  I have the following in my old kernel config:
>> # Statically Link in accept filters
>> options       ACCEPT_FILTER_DATA
>> options       ACCEPT_FILTER_HTTP
>> # Zero copy sockets support.  This enables "zero copy" for sending and
>> # receiving data via a socket.  The send side works for any type of NIC,
>> # the receive side only works for NICs that support MTUs greater than the
>> # page size of your architecture and that support header splitting.  See
>> # zero_copy(9) for more details.
>> options       ZERO_COPY_SOCKETS
>    I recall experiencing some crashes with ZERO_COPY_SOCKETS on
> RELENG_6 and it was related to the VM subsystem. Tor Egge may have a
> better idea about the problem and whether it was fixed in RELENG_7 or
> not.

I think it is believed to be fixed in 7.0, so it is worth testing.


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