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Re: Slowup in 2.1.54
From: |
Dmitri A. Sergatskov |
Subject: |
Re: Slowup in 2.1.54 |
Date: |
Tue, 17 Feb 2004 15:31:59 -0700 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040115 |
David Bateman wrote:
The gcd stuff might just be a timing error. The code used for the timing
in the sciview tests is pretty rough, using tic/toc. I've replaced this
in my version using cputime instead. and get the follow
cputime does not work with pthreads, so I have to use tic/toc.
Here is another example of recursion slowdown:
2.1.53:
tic; for n=1:1000; bm_x=sylvester_matrix(7) ; endfor ; toc
ans = 4.2025
2.1.54:
tic; for n=1:1000; bm_x=sylvester_matrix(7) ; endfor ; toc
ans = 11.574
(those are both stock releases no patches for SMP/pthreads etc...;
--enable-shared --disable-static ; -O3 -march=athlon-mp; AthlonMP x2)
So the only significant slow up I see is in the last test. Here is another
interting set of tests
2.1.50
tic; x = []; for i=1:1e3; x = [x, i]; endfor; toc
ans = 0.079843
tic; x=0; for i=1:1e3; x++; endfor; toc
ans = 0.018920
I do not trust tic/toc numbers less then 0.1 sec. So I increased the index:
2.1.53:
tic; x = []; for i=1:1e4; x = [x, i]; endfor; toc
ans = 3.2951
2.1.54:
tic; x = []; for i=1:1e4; x = [x, i]; endfor; toc
ans = 20.234
2.1.53:
tic; x=0; for i=1:1e4; x++; endfor; toc
ans = 0.024073
tic; x=0; for i=1:1e5; x++; endfor; toc
ans = 0.24130
tic; x=0; for i=1:1e6; x++; endfor; toc
ans = 2.3381
2.1.54:
tic; x=0; for i=1:1e4; x++; endfor; toc
ans = 0.028044
tic; x=0; for i=1:1e5; x++; endfor; toc
ans = 0.26263
tic; x=0; for i=1:1e6; x++; endfor; toc
ans = 2.6506
(I do not understand it, but my old records show that loops
were slower, it seems that something else in my system changed that
speeded it up.)
Regards
David
Sincerely,
Dmitri.
- Slowup in 2.1.54, David Bateman, 2004/02/17
- Slowup in 2.1.54, John W. Eaton, 2004/02/17
- Re: Slowup in 2.1.54, Dmitri A. Sergatskov, 2004/02/17
- Re: Slowup in 2.1.54, Paul Thomas, 2004/02/18
- Re: Slowup in 2.1.54, John W. Eaton, 2004/02/18
- Re: Slowup in 2.1.54, Paul Thomas, 2004/02/18
- Re: Slowup in 2.1.54, John W. Eaton, 2004/02/18
- Re: Slowup in 2.1.54, David Bateman, 2004/02/18
- Re: Slowup in 2.1.54, Paul Kienzle, 2004/02/18
- Re: Slowup in 2.1.54, Daniel J Sebald, 2004/02/18