[Gdal-dev] build help with threads- SOLVED

Stephen Woodbridge woodbri at swoodbridge.com
Tue Mar 13 22:58:28 EDT 2007


We upgraded to gdal 1.4.0 and that seemed to fix the problem.
Many thanks to mloskot on IRC for his help and guidance and for pointing 
out that I should be using --with-threads and not --enable-threads=posix

We are running! I had hoped we would see a big performance boost on a 
multi processor box with this option, but we get the same performance 
with and without the -multi option.

I have noticed that I can run two separate processes in about the same 
time as running one. I have a batchfile that does 164 gdalwarp commands 
and take 94 mins for one process, and 99 mins when 2 processes are 
running in parallel. The system has 8 virutal CPUs and the two processes 
run at nearly 100% cpu. So assuming the disk can keep up (not likely), I 
in theory should be able to run 8 processes. I think it would be easier 
to manage a fewer number of processes that run faster if that were 
possible, but we will deal with it.

-Steve

Stephen Woodbridge wrote:
> Hi all,
> 
> I am have trouble running gdalwarp with threads.
> 
> It is build like this:
> 
> ./configure
> --with-mrsid=/usr/local/mrsid
> --with-pg=/usr/bin/pg_config
> --enable-threads=posix
> 
> It builds without a problem, and it runs fine without -multi, but 
> running with the -multi option I get:
> 
> [swoodbridge at booboo compliance_fsa]$ gdalwarp -multi -s_srs 
> +init=epsg:26912 -t_srs EPSG:4326 -te -112.5625 41 -112.5 41.0625 -rb 
> -wm 250 --config GDAL_ONE_BIG_READ ON -co "TILED=YES" 
> ./naip_1-1_1n_s_ut057_2006_1.sid tiffs/B-112_41/B-112_41_247.tif
> Creating output file that is 5420P x 5420L.
> Processing input file ./naip_1-1_1n_s_ut057_2006_1.sid.
> ERROR 1: CPLCreateThread() failed in ChunkAndWarpMulti()
> 
> [swoodbridge at booboo compliance_fsa]$ gdalwarp --version
> GDAL 1.3.2.0, released 2006/05/02
> 
> Any idea what I'm doing wrong???
> 
> Thanks,
>   -Steve
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