Re: Deactivate TCP Hostcache?

From: Christian Vogt (chvogt_at_tm.uka.de)
Date: 08/20/05

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    Date: Sat, 20 Aug 2005 19:50:18 +0200
To: Andre Oppermann <andre@freebsd.org>

    Hi Andre,

    thanks for the info.

    What I did is this: I changed the TCP_HOSTCACHE_PRUNE constant from 5
    minutes to 5 seconds. After one experimentation run, my scripts call
    'sysctl net.inet.tcp.hostcache.purge=1 && sleep 5'.

    This guarantees that there is no remaining info in the TCP hostcache
    when the next experimentation run takes off.

    Bye,
    - Christian 

    --
Christian Vogt, Institute of Telematics, University of Karlsruhe
www.tm.uka.de/~chvogt/pubkey/
Andre Oppermann wrote:
> Christian Vogt wrote:
>
>>Hi everybody,
>>
>>is there a way to deactivate the TCP hostcache?
>>
>>I could modify the kernel, but probably there is a more convenient way
>>to do this.
>
>
> No, there is no other way.
>
>
>>The reason I want to deactivate the hostcache is because I am doing
>>experiments and later measurements should not be different than earlier
>>ones due to cached information.
>
>
> Comment out the tcp_hc_update() call on line 737 in netinet/tcp_subr.c
> and it won't cache metrics anymore.  The discovered path MTU is still
> stored though.
>

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