[vtkusers] vtkVolumeRayCastMapper - Threads Reported

[Lisa Avila]

Hello Ravi,

The class you should look at is vtkMultiThreader which provides the 
threading capability for a number of VTK classes. There are some system 
calls made to attempt to determine how many available CPUs there are for 
processing - obviously you have encountered a problem in this detection 
code. I am not sure what you mean by "allocating" here - how are you 
restricting the number of CPUs? What do you mean by "SetNumberOfThreads(int 
num) has not worked"? The number of threads should equal what you set it to 
- unless that is more than some upper limit (32 as defined in 
vtkSystemIncludes.h".

Lisa




At 09:15 AM 7/9/2003, Ravi Gupta wrote:
>  Hi,
>
>I was wondering if the following is a bug and/or if there is a way around 
>this.
>
>On a 2 CPU system vtkVolumeRayCastMapper reports 2 threads and 2 CPUs get 
>used.
>On a 4 CPU system vtkVolumeRayCastMapper report 4 threads and 4 CPUs get used.
>
>I ran a bunch of tests on SGI and SUN systems
>IRIX64 6.5 01091821 IP30
>SunOS 5.8 Generic_108528-18 sun4u sparc SUNW,Sun-Fire-880
>
>SGI - 32 CPU system allocating 32 CPUs 32 threads are reported and 32 CPUs 
>get used.
>SGI - 32 CPU system allocating 8 CPUs 24 threads are reported and 8 CPUs 
>get used.
>SGI - 32 CPU system allocating 4 CPUs 28 threads are reported and 4 CPUs 
>get used.
># threads + # CPUs used = Total # CPUs on the system.
>
>SUN - 8 CPU system allocating 8 CPUs 8 threads are reported and 8 CPUs get 
>used.
>SUN - 8 CPU system allocating 4 CPUs 8 threads are reported and 4 CPUs get 
>used.
># threads = Total # CPUs on the system.
>
>On a 2 CPU Xeon Linux Redhat 8 system run to show 4 CPUs only 2 threads 
>get reported and only 2 CPUs get used.
>
>So my question is how do I get my code to have # Threads = # CPUs 
>Allocated/available.
>
>SetNumberOfThreads (int num) has not worked.
>
>Thanks
>Ravi
>
>--
>Ravi Gupta
>
>Programmer
>
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>Robarts Research - Imaging        | 100 Perth Drive
>Tel: (519) 663-5777 ext. 1-34077  | London, Ontario
>Fax: (519) 663-3403               | N6A 5K8
>E-Mail: rgupta at imaging.robarts.ca | Canada 
>###################################################
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>http://www.imaging.robarts.ca/
>http://www.imaging.robarts.ca/coders    http://www.imaging.robarts.ca/~rgupta
>###################################################
>
>"Be the change you wish to see in the world."
>-Mohandas Karamchand Gandhi
>
>
>
>--
>Ravi Gupta
>
>Programmer
>
>###################################################
>Robarts Research - Imaging        | 100 Perth Drive
>Tel: (519) 663-5777 ext. 1-34077  | London, Ontario
>Fax: (519) 663-3403               | N6A 5K8
>E-Mail: rgupta at imaging.robarts.ca | Canada 
>###################################################
>
>###################################################
>http://www.imaging.robarts.ca/
>http://www.imaging.robarts.ca/coders    http://www.imaging.robarts.ca/~rgupta
>###################################################
>
>"Be the change you wish to see in the world."
>-Mohandas Karamchand Gandhi
>
>
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