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Date:      Wed, 04 Mar 2009 22:05:53 +0100
From:      Sebastian Mellmann <sebastian.mellmann@net.t-labs.tu-berlin.de>
To:        Luigi Rizzo <rizzo@iet.unipi.it>
Cc:        freebsd-ipfw@freebsd.org
Subject:   Re: ipfw (dummynet) adds delay, but not configured to do so
Message-ID:  <49AEED31.8060801@net.t-labs.tu-berlin.de>
In-Reply-To: <20090304210017.GA29615@onelab2.iet.unipi.it>
References:  <49AED3B1.1060209@net.t-labs.tu-berlin.de> <20090304210017.GA29615@onelab2.iet.unipi.it>

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> On Wed, Mar 04, 2009 at 08:17:05PM +0100, Sebastian Mellmann wrote:
>   
>> Hi everyone!
>>
>> I hope this is the right place to ask.
>>
>> I've got a IPFW ruleset that looks like this:
>>
>> cmd=ipfw
>> bottleneck_bandwidth=100Mbit/s
>> in_if="em0"
>>
>> $cmd pipe 500 config bw $bottleneck_bandwidth
>> $cmd add pipe 500 all from any to any via $in_if
>>     
>
> the delay that a packet experiences corresponds to len/bandwidth,
> often rounded up to the next clock tick (1ms is the default).
> You get one delay inbound, one delay outbound, so that's 2ms.
>
>   
Is there any chance to change this clock tick to a lower value?
I think it's the 'HZ=' option in the kernel config isn't it?

> cheers
> luigi
>   


Regards,
Sebastian



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