[Bridge] Bridge performance problem

Chris Shaw chriss at watertech.com
Fri Aug 27 08:42:54 PDT 2004

> Would you mind explaining what the txqueuelen does?  Or point me to a
> location I can read about it?  More about wanting to know what it does
> than anything else.

The TXQUEUELEN parameter is strictly for QoS, namely the PFIFO Scheduler, it
sets the Queue length for that scheduler and that's all I think it does...

> BTW, can you enable NAPI dynamically on the driver?  Or is this a
> compile time only option?

Compile-Time only I believe, it changes the driver code a bit where
interrupt handling is done I think...

> Finally, just to see if it was a software issue or hardware issue, I
> kept the OS/software the same and install on a new machine.  New
> machine/different NICS.  In this case I saw much improved performance.
> Whereas before I was taking a 45% hit, on this new hardware I was taking
> a 17% hit.  This make me think I have a hardware problem.

This concerns me a bit, I have a Dual-Port E1000 server adapter and I've
been very happy with it's operation, I do notice however that it could be
faster... The only other GbE NICS I've tried  have been NatSemi 83820-Based
and a Marvell OnBoard GbE NIC, both of which suck out loud as far as
performance goes... The Marvell one especially, it has some kind of wierd
timeout issue when receiving packets, a TCP dump shows it intermittently
pausing for like 2 seconds every 10 seconds or so... I could never figure
that one out...


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