Fwd: [GRASS-dev] multi-threaded r.mapcalc

[Markus Neteler]

On Fri, Jan 9, 2009 at 5:51 PM, Glynn Clements <glynn at gclements.plus.com> wrote:
> Markus Neteler wrote:
>
>> > I have added experimental multi-threading support to r.mapcalc in 7.0
>> > (r34440). It isn't enabled by default; to enable it, use
>> > "make USE_PTHREAD=1". It only uses a handful of pthread functions, so
>> > there's a reasonable chance of it working on MacOSX and/or Windows
>> > (with the pthread-win32 library).
>> >
>> > You can change the number of worker threads by setting the WORKERS
>> > environment variable.
...
> r.shaded.relief seems to have the most complex r.mapcalc expression of
> any of the supplied scripts.

I have built r.mapcalc with 'make USE_PTHREAD=1' in 7,
this are the results:

GRASS 7.0.svn (nc_spm_07):~ > g.region rast=elevation -p
...
cells:      2025000

GRASS 7.0.svn (nc_spm_07):~ > time r.shaded.relief elevation
Calculating shading, please stand by.
 100%
Color table for raster map <elevation.shade> set to 'grey'
Shaded relief map created and named <elevation.shade>. Consider renaming.
9.22user 1.54system 0:09.63elapsed 111%CPU (0avgtext+0avgdata 0maxresident)k
56inputs+29960outputs (0major+53040minor)pagefaults 0swaps

GRASS 6.5.svn (nc_spm_07):~ > g.region rast=elevation
GRASS 6.5.svn (nc_spm_07):~ > time r.shaded.relief elevation
Calculating shading, please stand by.
 100%
Color table for raster map <elevation.shade> set to 'grey'
Shaded relief map created and named <elevation.shade>. Consider renaming.
10.68user 0.40system 0:11.13elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
8inputs+29968outputs (0major+48438minor)pagefaults 0swaps

Markus