[gmx-users] which item is gpu wait for cpu?

[xiexiaobin at sjtu.edu.cn]

Thanks.And I have another question want to ask.
I used the command "mdrun_mpi -v -deffnm test" to run the .tpr file and find some new information in my log file:

 GPU timings
-----------------------------------------------------------------------------
Computing: Count Wall t (s) ms/step %
-----------------------------------------------------------------------------
Pair list H2D 501 0.364 0.726 0.4
X / q H2D 20001 4.153 0.208 4.5
Nonbonded F kernel 18800 77.657 4.131 84.5
Nonbonded F+ene k. 700 4.060 5.800 4.4
Nonbonded F+prune k. 400 2.121 5.303 2.3
Nonbonded F+ene+prune k. 101 0.717 7.103 0.8
F D2H 20001 2.873 0.144 3.1
-----------------------------------------------------------------------------
Total 91.946 4.597 100.0
-----------------------------------------------------------------------------

Force evaluation time GPU/CPU: 4.597 ms/5.245 ms = 0.876.

But I used to use the some command and didn't appear such information.Does anyone know why?
I also find that the time consuming of Nonbonded F kernel is 77.657s but the time consuming of force is only 55.263s.Does the force item include non-bonded force?If it was true,why the Nonbonded F kernel takes more time than the force ?



xiexiaobin at sjtu.edu.cn
 
From: Szilárd Páll
Date: 2014-09-24 17:45
To: Discussion list for GROMACS users
CC: gromacs.org_gmx-users
Subject: Re: [gmx-users] which item is gpu wait for cpu?
On Wed, Sep 24, 2014 at 4:57 AM, xiexiaobin at sjtu.edu.cn
<xiexiaobin at sjtu.edu.cn> wrote:
> I think that the items (wait GPU nonlocal) and (wait GPU local) in log file are the time consuming that cpu wait for gpu. And Does anyone know that which item is the time consuming that gpu wait for cpu in log file?
 
Due to a CUDA runtime limitation, that can not measured except for the
no domain-decomposition case (where it is expressed as overlap).
 
>
>
> xiexiaobin at sjtu.edu.cn
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