From owner-freebsd-current  Mon Apr 20 08:14:36 1998
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To: Scott Michel <scottm@cs.ucla.edu>
cc: current@FreeBSD.ORG
Subject: Re: Networking strategy for -current 
In-reply-to: Your message of "Sun, 19 Apr 1998 16:37:42 MST."
             <199804192337.QAA05685@mordred.cs.ucla.edu> 
Date: Mon, 20 Apr 1998 23:46:36 +0900
From: Kenjiro Cho <kjc@csl.sony.co.jp>
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Scott Michel said:

>> Kenjiro's work is spectacular for low speed and medium speed
>> links (<= 10Mbs). For 100Mbs links, well, ... let's just say
>> it appears to have a lot of overhead.

>> I'm not sure whether it's Matt Thomas' de driver which is the
>> issue (certainly, the driver code needs some simplification)
>> or if ALTQ requires the send interrupt to be triggered so that
>> he knows a packet has drained.

It's not the overhead of CBQ.

 o CBQ needs a fine-grained kernel timer (say 1KHz) for 100baseT.
   It's the design of the original CBQ. (a simple math proves it,
   MTU of 100baseT is too small for 100Mbps)

 o There is a problem in the de driver patch of altq-0.4.3.
   (de driver is too clever and too complex :-)
   Some improvement is added in altq-1.0.1.

If you still have problems with altq-1.0.1 with a fine-grained timer,
let me know.

--Kenjiro

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