tigon3: 2466 and bad performance at 32bits/33mhz ?

From: Robert Latham (robl@mcs.anl.gov)
Date: Tue Aug 06 2002 - 00:35:08 EST

I've got a 3com 3C996B-T (copper) and a tyan 2466 motherboard. The
kernel is 2.4.19-rc1-ac2, and i'm using the tg3 v0.99 (Jun 11, 2002).

When i run the 3C996B-T in the 64-bit/66-MHz slot, i get great
performance. When i run the card in the 32-bit/66-MHz slot, i get
pretty bad performance. Here's a netpipe graph to demonstrate:


The fast curve is with the 3c996B-T in the 64/66 slot. It peaks out
around 850 Mbps. The slow curve is the same card in the 32/33 slot.
It peaks around 180 Mbps.

Is a maximum throughput of ~180 MBits/sec all that can be hoped for? I
don't have the hardware to verify, but
offers the datapoint of 436 MBits/sec in an oldish dell optiplex ( old
being whenever p3 500 mhz machines were still made)

So, am i looking at a hardware limitation? driver quirk? I'm open to
any suggestions.

I'll keep an eye on the web archives, but please CC me on any replies.


Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Labs, IL USA                B29D F333 664A 4280 315B
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

This archive was generated by hypermail 2b29 : Wed Aug 07 2002 - 22:00:30 EST