On Thu, 2007-10-18 at 16:56 +1000, skaller wrote: > On Tue, 2007-10-16 at 17:40 +1000, skaller wrote: > > On Mon, 2007-10-15 at 03:26 +1000, skaller wrote: > > > Preliminary tests with Ubuntu-gutsy, gcc 4.2.1 with -fopenmp and some > > tutorial examples show openmp SLOWS down code going from 1 to 2 threads > > on a dual core AMD64x2 by a massive amount. The examples do appear to > > work correctly. The CPU monitor definitely pushes both cores > > up to 100%. > > Retesting with -O3 on advice of Joe Buck, the coarse parallelism > test finally ran faster with 2 threads than 1. > > The fine test (order 1K FLOPS) used 3 times more CPU total, > so took 50% more time on a dual core.
But the LU_mp.c test code had a bug (j was shared instead of thread private). After fixing it, 2 threads run 50% faster on my dual core! -- John Skaller <skaller at users dot sf dot net> Felix, successor to C++: http://felix.sf.net ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Felix-language mailing list Felix-language@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/felix-language
