[Beowulf] cluster softwares supporting parallel CFD computing

Daniel Kidger daniel.kidger at clearspeed.com
Wed Sep 6 08:34:45 PDT 2006


Parallel applications with lots of MPI traffic should run fine on a cluster
with large jiffies - just as long as the interconnect you use doesn't need to
take any interrupts. (Interrupts add hugely to the latency figure)


-----Original Message-----
From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On
Behalf Of Bogdan Costescu
Sent: 06 September 2006 14:56
To: Mark Hahn
Cc: Beowulf List
Subject: Re: [Beowulf] cluster softwares supporting parallel CFD computing

On Mon, 4 Sep 2006, Mark Hahn wrote:

> 100 Hz scheduler ticks might make sense

Please don't mention this to beginners (which is the impression that 
the original message left me) - if they care enough to search the 
information available on the subject they will either make their own 
mind or come back here to ask a specific question...

Higher scheduler frequency was demanded, among others, by network 
developers who see the backlog run at this frequency - when this is 
too low, the network latency in certain situations increases which is 
undesired for most cluster applications.

IMHO, low scheduler frequency is probably only good for mostly 
computational jobs (f.e. Monte Carlo style) where such latency doesn't 
matter and the small amount of time saved due to the lower number of 
context switches is used for real computations.

Bogdan Costescu

IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen
Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY
Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868
E-mail: Bogdan.Costescu at IWR.Uni-Heidelberg.De
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