External Email - Use Caution

Hi Vasudev,

in case you use v6, you can use the -parallel flag to process the hemispheres (and a few other things if I remember correctly) in parallel. Note that doing so will parse the -openmp flag to all instances. E.g.

recon-all -all -openmp 4 -parallel -s subjID -i inputFile

Also the reduction in processing time using openmp is limited – I don’t recall exactly if it was bound to the number of physical cores your CPU has or if it was an upper limit to due the way the parallelization works (I have something like in mind like not much of an increase beyond openmp 8).

Best, Falk

Von: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu Im Auftrag von Dev vasu Gesendet: Mittwoch, 18. September 2019 15:08 An: freesurfer@nmr.mgh.harvard.edu Betreff: [Freesurfer] How to fasten recon-all execution time without using CUDA

External Email - Use Caution Dear all,

I am using - openmp 30 to run recon-all, i see now change in the execution time period.

Could you please highlight me a method to reduce the execution time for recon-all, if possible some parallel script to do that same.

Thanks Vasudev

Hi Vasudev

-openmp N is the best way at the moment. Do you actually have 3 cores to dedicate? Usually due to memory access speeds and such we don't see much gain after N=4, but I'm surprised there is no effect cheers Bruce On Wed, 18 Sep 2019, Dev vasu wrote:

External Email - Use Caution

Dear all,

I am using - openmp 30 to run recon-all, i see now change in the execution time period.

Could you please highlight me a method to reduce the execution time for recon-all, if possible some parallel script to do that same.

Thanks Vasudev