Slowness problem due to sjlj-exceptions for Octave

Carlo Florendo
Wed Sep 5 01:17:00 GMT 2007


Ohayougozaimasu :)

> I'm Tatsuro MATSUOKA.
> This is the first time to post cygwin-app ML.


> I'm now using cygwin for octave, gnuplot and shell command etc.
> For the Octave society, it is very famous that building octave 
> current standard gcc slows the octave
> because the cygwin treats the silj-exceptions very slowly. 

Could you please expound (or point to a link) on what sjlj or sjlj- 
exceptions do?  AFAIK, it's probably the first time the "octave sjlj 
exception issue" has appeared in this list.  As far as I've seen, this is a 
gcc issue.

> I do not entirely agree with his opinion, but I also have a question 
> on sjlj-problem on cygwin.
> This problem has been famous for a long time in the Octave society. I 
> suppose it has been also
> disscussed in cygwin ML.  My question is why the cygwin uses the slow 
> sjlj exceptions instead of
> dwarf2 which was used in old cygwin at the time gcc-3.2 was used.

The cygwin octave maintainer (if [s]he is still there) must know more about 
this.  However, Cygwin's octave is 2.1.72 but mainline is 2.9.13.

> Recetly the Octave can be built with the mingw. The mingw GCC also 
> uses sjlj exceptions but the
> slowness problem never be occured.  
> I wonder why the sjlj exceptions slows the octave on cygwin.  In 
> other platforms including mingw, such
> phenomea does not happen.  

Would it be possible for you to send corresponding straces of the cases you 
posted below?

> Using Oregonator ODE (source was placed at the end of the
> mail), we compare the solving time
> octave 2.9.13 built with  gcc-3.4.4-3 in cygwin package 
> octave:1> testOregoB
> ans =  9.2500
> octave 2.1.73 binary in cygwin package
> octave:1> testOregoB
> ans = 7.0930
> my testing binary built specially confgiured gcc.
> octave:1> testOregoB
> ans =  2.7030          

Regarding these "testing binary" and "specially configured gcc", what 
versions are these and what options did you use to build gcc?

Thank you very much!

Best Regards,


Carlo Florendo
Software Engineer/Network Co-Administrator
Astra Philippines Inc.
UP-Ayala Technopark, UP Campus Diliman
1101 Quezon City, Philippines

The Astra Group of Companies
5-3-11 Sekido, Tama City
Tokyo 206-0011, Japan

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