Processor contention(?) and network bandwidth on AMD

Joshua Baker-LePain jlb17 at duke.edu
Mon Apr 29 15:49:32 EDT 2002


On Mon, 29 Apr 2002 at 3:40pm, Mark Hahn wrote

> well, there are several contributing factors, which are probably
> mitigated by running a decently modern (ie 2.4.18) kernel.
> 
> for instance, at gigabit speeds, you're almost certainly generating
> nontrivial MM load.  there's been a huge amount of improvement in 2.4's
> in how they handle ram.

These tests (obviously) were only at FE speed, though.  The receiving end 
was gigabit, but the sending end (the dual AMD nodes) was FE.

> > unloaded:                                         11486.6 KB/real sec
> > 2 matlab simulations:                             10637.8 KB/real sec
> > 2 matlab simulations and 2 SETI at homes (nice -19):  6645.4 KB/real sec
> 
> SETI at home is obviously in the "so don't do that" category.  I expect your
> matlab was decelerated by a similar amount.

Sure, but it was just an example of a niced background load, which 
"shouldn't" interfere with anything.  It certainly shouldn't crash 
bandwidth like that.

> > tested (dual PIII 933 on an i860) showed very little bandwidth drop with 
> 
> i860 is a P4 chipset afaik...

Oops -- not enough coffee.  I meant i840.  Dual PIII with RDRAM.

-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University

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