Re: octave dev slow down

[Mike Miller]

On Mon, May 22, 2017 at 23:48:10 -0500, Dmitri A. Sergatskov wrote:
> I run some benchmarks with the recent dev vs 4.2.1 and noticed a
> significant slowdown
> for the following test:
> 
> a=randn(4000);
> tic; a'*a; toc
> For both runs I LD_PRELOAD=/usr/lib64/atlas/libtatlas.so
> and then repeat with LD_PRELOAD=/usr/lib64/atlas/libsatlas.so
> 4.2.1:
> 
> Elapsed time is 1.61557 seconds. (t)
> Elapsed time is 5.02009 seconds. (s)
> 
> hg id
> ed2239ed5fd3 tip @
> 
> Elapsed time is 2.78834 seconds. (t)
> Elapsed time is 9.69433 seconds. (s)
> 
> Most of other benchmarks (like inv(a)*a, a\b are pretty much the same).

Confirmed here. I bisected and found a lot of performance loss starting
with c452180ab672. Its immediate predecessor f4d4d83f15c5 has about the
same performance as 4.2.1. If you can compare those two revisions and
confirm, that's a good place to start looking for a cause.

-- 
mike