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Re: NAPI-ized tulip patch against 2.4.20-rc1

To: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>
Subject: Re: NAPI-ized tulip patch against 2.4.20-rc1
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Thu, 07 Nov 2002 13:25:54 -0800
Cc: "'netdev@xxxxxxxxxxx'" <netdev@xxxxxxxxxxx>
Organization: Candela Technologies
References: <Pine.GSO.4.30.0211070823590.11358-100000@shell.cyberus.ca> <Pine.LNX.4.44.0211071013150.31376-100000@grok.yi.org> <15818.55916.259489.688198@robur.slu.se>
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Robert Olsson wrote:
greear@xxxxxxxxxxxxxxx writes:
> On Thu, 7 Nov 2002, jamal wrote:
> > Trash the machines harder. Try using smaller packets;
> > They are already dropping packets, I thought I'd try to get a slower run > to work cleanly before trying something faster. Precision is more
> important to me than absolute throughput at this point.



If you need excessive buffering this gives latency and jitter which is considered bad for network protocols and worse for test equipment.

It depends on the goals of the test, but I agree in principle :)

> Initial run with 256 sized rx-ring (and skb-recycle) shows better
> performance (than with 1024 rx-ring)
Packet size? Expect eventual effects when there is very high pressure on the packet memory system.

Packet size has been 1514 for all my recent tests.

For an extended 256 rx-ring run (4kpps send + rcv, 1514 byte packet, 4 ports),
I see about 9k dropped packets per 55 million sent & received.

Ben


Cheers.
--ro




--
Ben Greear <greearb@xxxxxxxxxxxxxxx>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear



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