Re: Perfromance problem running multiple copies of Octave on a multicore processor

[Olaf Till]

On Thu, Dec 10, 2015 at 01:46:53PM +0000, Ian McCallion wrote:
> Hi Olaf,
> 
> Here is the code. ldd is unix-only so haven't done the commands you
> suggested. However I will send you the win equivalent shortly.
> 
>  The cmd script is how I switch blas versions.

Since you are using Windows, I couldn't check if your procedure indeed
provides the same library to both Octave versions. You seem to assume
that Octave uses the .dll version that is in the same directory as its
own executable file; I have no notion if this is the case in
Windows. But the point is that indeed physically identical blas
library files have to be used by both Octave versions for testing. I
still suspect different libraries could have been used.

I didn't run your code, but you should not measure the duration of
only the first proces (in perf2), but of all parallel processes
(i.e. the duration from before 'for i = 1:nProc' till after

for i = 1:nProc
  mwait (pid(i));
endfor

in perf1. But I daresay the outcome will probably not be
different. Otherwise your code seems to correctly test the duration of
matrix multiplication.

Olaf

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