Re: AW: problem with +devices using

From: nikolaev_at_spbau.ru
Date: Tue Apr 05 2016 - 07:41:17 CDT

Well, I tried the taskset and everything works fine now, thank you.

I also attach the cpuinfo here, just in case.

> Ignoring the fact that the shared PCIE bus will cause a smaller
> performance drop anyway, your significant slowdown may be caused by using
> the same cpus for your both jobs. Show us the output of
>
> cat /proc/cpuinfo
>
> You need to make sure each job will only use its subset of cpus. You can
> accomplish that using taskset, depending on how many cores you have. An
> example for a machine which would have 16 cores:
>
> taskset -c 0-7 namd2 +p8 A.conf
>
> taskset -c 8-15 namd2 +p8 B.conf
>
> Norman Geist
>
>> -----Urspr√ľngliche Nachricht-----
>> Von: owner-namd-l_at_ks.uiuc.edu [mailto:owner-namd-l_at_ks.uiuc.edu] Im
>> Auftrag von nikolaev_at_spbau.ru
>> Gesendet: Dienstag, 5. April 2016 13:35
>> An: namd-l_at_ks.uiuc.edu
>> Betreff: namd-l: problem with +devices using
>>
>> Hello,
>>
>> I use a CUDA build of NAMD, and want to run 2 jobs simultaneously.
>> We have 4 devices, so I assign +devices 0,1 for the first job and
>> +devices 2,3 for the second.
>> When I run the first job, everything is ok, and it runs well on 2
>> devices
>> and uses 65-70% of the devices' resources.
>> But when I add the second job, the performance drops immediately to 10-
>> 11%
>> on all 4 devices!
>>
>> How to solve this problem?
>>
>> Here is the command I run namd:
>>
>> /home/nikolaev_d/NAMD_2.11_Linux-x86_64-multicore-CUDA/namd2
>> +setcpuaffinity +p18 +devices 0,1 +idlepoll A.conf > A.log
>>
>> Thank you in advance,
>> Dmitrii.
>>
>
>
>
>


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