From help-octave-request at bevo dot che dot wisc dot edu Fri Jan 16 18:04:41 2004 Subject: Re: Octave and threaded ATLAS and FFTW From: "Dmitri A. Sergatskov" To: "John W. Eaton" Cc: help-octave Date: Fri, 16 Jan 2004 17:03:01 -0700 John W. Eaton wrote: > I think it would be worth an attempt just to see what happens, but I > don't have time (or the need) to do it myself. If you do it, please > post your results to the list. I did compile octave 2.1.50 with pthreaded atlas. Though it mostly work and some benchmarks show improvements. E.g. from (in)famous Octave2 benchmark (which was discussed on octave-maint. list) "normal" ATLAS: 700x700 cross-product matrix (b = a' * a)___________ (sec): 0.2713 "pthreded" ATLAS 700x700 cross-product matrix (b = a' * a)___________ (sec): 0.1727 I am not quite sure yet those are real numbers since I discovered that "cputime" does not work as expected any more (at least not as I expected): octave:2> tic; t1=cputime ; a=rand(2000); t2=cputime ; toc ans = 0.16871 octave:3> t2-t1 ans = 0.16000 (That is probably close enough) octave:4> tic; t1=cputime ; b=inv(a); t2=cputime ; toc ans = 7.3011 octave:5> t2-t1 ans = 1.8600 (7.3 seems more real here) octave:9> tic; t1=cputime ; c=b*a; t2=cputime ; toc ans = 2.9955 octave:10> t2-t1 ans = 0 (Well...) octave:12> tic; t1=cputime ; ifft(fft(a)); t2=cputime ; toc ans = 1.5286 octave:13> t2-t1 ans = 1.5000 (Looks OK again) So all BLAS/LAPACK benchmarks which use "cputime" are greatly improved :) (Octave2 uses tic; toc method.) Frankly, by reading ATLAS docs, I do not understand why would I get any improvements since ATLAS by itself will not spawn separate tasks... > Thanks, > > jwe Sincerely, Dmitri. p.s. The tests done on AthlonMPx2 2000 MHz. Octave2 is from http://www.sciviews.org/other/benchmark.htm ATLAS 2.6.0 which I compiled myself. ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------