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mrtrix_usage [2016/12/20 19:46]
mgstauff created
mrtrix_usage [2017/06/02 15:27] (current)
mgstauff [Multi-threading]
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 Similar to Matlab, MRtrix will, by default, spawn as many threads as it sees cores on the compute node where it's running. This will cause problems and significantly slow down the whole node. To prevent this, multi-threading should be disabled or carefully set to match the number of slots/cores assigned to your job. Similar to Matlab, MRtrix will, by default, spawn as many threads as it sees cores on the compute node where it's running. This will cause problems and significantly slow down the whole node. To prevent this, multi-threading should be disabled or carefully set to match the number of slots/cores assigned to your job.
  
-===Disabled by default===+===MRTRIX_NTHREADS defaults to NSLOTS===
  
-The /etc/mrtrix.conf configuration file is set on chead and on each node to disable multi-threading by default, by assigning the NumberOfThreads parameter to 0.+As of approximately December 21, 2016, MRTrix will read the environment variable ''MRTRIX_NTHREADS'' to globally set the number of threads it should use. By default when you login or start a new qlogin or qsub job, the CfN cluster settings assigns the SGE ''NSLOTS'' var to ''MRTRIX_NTHREADS'', so that MRTrix will run with the same number of threads as the requested number of cores/slots for your job.
  
-===How to enable multi-threading===+===How to override multi-threading===
  
-In your script when you call MRtrix, include ''-nthreads $NSLOTS''. This will set up multi-threading for the number of slots/cores your job has.+If for some reason (be sure about this!) you need to override the setting, you can do so in your script when you call an MRtrix commandby including the command line option ''-nthreads <N>'' in your , where N is the number of threads
mrtrix_usage.1482263168.txt.gz · Last modified: 2016/12/20 19:46 by mgstauff