[Omp] A basic question about OpenMP

[Richard Friedman]

On Solaris with the Sun Studio 12 compilers you can bind threads to 
processors.
See section 2.4 in the OpenMP User's Guide
http://docs.sun.com/app/docs/doc/819-5270/6n7c71vd4?a=view

aduran at ac.upc.edu wrote:
> Abhijit,
>
> Quoting Abhijit Joshi <joshi1974 at gmail.com>:
>
>   
>> During OpenMP implementation, is *thread* = *processor* ?
>>     
>
> Not necessarily. That's an implementation detail that is not specified in the
> standard. It may be a 1 to 1 equivalence or it may not. You should check the
> documentation of the OpenMP implementation you use.
>
>   
>> For example, when
>> I run the OpenMP version of my code using 5 threads, I find that only one
>> processor is being used, but usage of that processor is 500% (using the top
>> command).
>>     
>
> The newest versions of top collapse by default the percentages of all cpus into
> a single one, so that 500% in fact most probably means 5 cpus working at a 100%
> (although it could also a higher number of cpus at a lower % :). You can press
> number '1' from top to show all cpu percentages.
>
>   
>> within my code to set the number of "threads" to 5. Apparently, this the not
>> the same as the number of processors. Is there another command to set the
>> number of processors ?
>>     
>
> No. You can only specify the number of OpenMP threads.
>
> Regards,
> Alex
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> http://openmp.org/mailman/listinfo/omp
>   

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