[gdal-dev] gdal_translate and multithreading

[Pierre Soille]

Hello,

while translating a vrt file into a tif file with gdal_translate, I
noticed thanks to htop utility that gdal_translate is using
multithreading (typicallay 4 threads). I fail to find any multithreading
option for gdal_translate (contrary to gdal_warp that has a multi option
and where the number of threads can be set with -wo "NUM_THREADS=x"). 
Is there any possibility to prevent gdal_translate from multithreading? 
Setting the global environment variable OMP_NUM_THREADS to 1 does not
help.  I had a quick look to gdal_translate.cpp but did not find any
explicit reference to multithreading.

This behaviour of gdal_translate is an issue in case of distributed
computing.  Indeed, cluster nodes with many cores are spending most of
their time with kernel time to serve a number of threads largely
exceeding the number of CPUs.

Any hint on how to solve this problem will be greatly appreciated.

Cheers,

Pierre

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Pierre Soille
EC Joint Research Centre
Ispra, Italy
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