Hi Cao,
How many cores total do you have in your machine? As soon as you are using
more cores than you physically have you will likely a massive slow down in
all the calculations due to cache thrashing and the fact there are many
latencies associated with multiple thread scheduling.
Simple answer is do not use more cores than you have physical cores on the
machine. Wait for the 24 core job to finish and then start the 2 core job.
All the best
Ross
> -----Original Message-----
> From: Cao Yang [mailto:muxiachuixue.163.com]
> Sent: Tuesday, June 19, 2012 3:52 AM
> To: Amber
> Subject: [AMBER] Slow jobs
>
> Hi all,
> I did MD calculation with AMBER and quantum chemistry calculation with
> GAUSSIAN on a 24 CPUs machine.
>
> Once the CPUs were 100% used, I submitted a two-CPUs-costed job. What
> confused me is that all jobs including AMBER and GAUSSIAN became
> extremely slow.
>
> Can anyone explain the slowness? Thanks.
>
> Cao Yang
>
>
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Received on Tue Jun 19 2012 - 09:30:02 PDT
