performance issue

Sterling Augustine sterling at tensilica.com
Fri Feb 24 19:37:40 UTC 2006


Mike Frysinger wrote:
> On Friday 24 February 2006 12:18, Sterling Augustine wrote:
> 
> i know multibyte handling is slow (if it works at all), but are you referring 
> to normal ASCII string handling ?  if so, what target ?  are you utilizing 
> the C-only versions (which i would understand if they were slow) or did you 
> try the asm-tuned versions ?

My original port to Xtensa, which originally used the c versions because 
I didn't know any better. When I did performance analysis, the problem 
showed right up, I subistituted my own hand-tuned asm, and performance 
matched the other c libs out there.

I don't know what port the original poster is using. But if his port 
doesn't have the hand-tuned asm functions, then that is really the only 
place in my experience except malloc and [s|f|vf]printf that could be 
causing him performance issues.

In you are spending an inordinant amount of time in malloc, then you 
should probably write a custom allocator anyway.

Now, I don't have a linux host underneath me, so I don't use threads, 
dynamic loading or networking out of uclibc. Perhaps if his code is 
spending a lot of time there. But, as far as I can tell uclibc is as 
fast as anything out there in the performance sensitive portions of 
applications.



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