[gdal-dev] [NEW] Multi-threaded warping

[Even Rouault]

Hi,

I've just commited in trunk the capability of doing multi-threaded warping. 
There was already a -multi option of gdalwarp that was used to parallelize I/O 
operations and warping computations. There's now a NUM_THREADS warping option 
that can be used to set the number of threads to parallelize the warping 
computations themselves. The value can be either a numeric value or ALL_CPUS 
to use all the available CPUs/cores. The best performance is achieved when 
used in combination with PROJ 4.8.0 or later, which allow SRS transformations 
to be done in parallel (when an older version is used, GDAL uses a global 
mutex to serialize SRS transformations). The new option is of course mostly 
useful when warping is CPU bound, for example when using complex warping 
kernels, such as cubic or lanczos.

For example :

gdalwarp [-multi] src.tif dst.tif -wo NUM_THREADS=ALL_CPUS

Please test and report if you have issues.

Best regards,

Even