how can i tell re: the thrashing?<br>Zach<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Message: 3<br>
Date: Sun, 26 Dec 2010 05:29:31 -0600<br>
From: Pavan Balaji <<a href="mailto:balaji@mcs.anl.gov">balaji@mcs.anl.gov</a>><br>
Subject: Re: [mpich-discuss] quad core mpich2 sluggish<br>
To: <a href="mailto:mpich-discuss@mcs.anl.gov">mpich-discuss@mcs.anl.gov</a><br>
Cc: zach <<a href="mailto:zachlubin@gmail.com">zachlubin@gmail.com</a>><br>
Message-ID: <<a href="mailto:4D17271B.5070100@mcs.anl.gov">4D17271B.5070100@mcs.anl.gov</a>><br>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed<br>
<br>
Zach,<br>
<br>
It's hard to tell what is going on based on the description below. Is<br>
your application thrashing memory/cache? Are you using the same problem<br>
size with increasing number of processes?<br>
<br>
-- Pavan<br>
<br>
On 12/24/2010 12:33 PM, zach wrote:<br>
> I am running the latest ubuntu with a Q6600 quad core cpu and the mpich2<br>
> that came with ubuntu<br>
> I can run my parallelized code over the four cores (i see it in 'top')<br>
> however, the speed increase over a single process is hardly improved for<br>
> 2,3, or even 4 processes.<br>
><br>
> i was able to run the same code on a linux cluster through my school<br>
> with speed increases as expected.<br>
> am i doing something wrong?<br>
><br>
> zach<br>
><br>
><br>
><br>
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<br>
--<br>
Pavan Balaji<br>
<a href="http://www.mcs.anl.gov/%7Ebalaji" target="_blank">http://www.mcs.anl.gov/~balaji</a><br>
<br>
</blockquote></div><br>