[Kst] Hot paths

[George Staikos]

On Friday 17 December 2004 09:42, Barth Netterfield wrote:
> Seems to me: Not a lot...

   I figured the same.

> We could in principle get rid of some ifs at the cost of code size and
> complexity:
>  -different loop for log and not log (chunk wise XY computation loops with
> the 'if' outside it)
>  -let vectors decide in advance if they have nans, different loop if no
> nans - loose another if. (no help in general, but, if some vector sources
> like data sources can't ever give nans then we don't have to test.  Or,
> for, scrolling data, we could cache past answers)
>  -we could cache X1 and Y1.
>
> This is all pretty painful, but could give a 30% speedup in our dreams.
> We will see a *much* bigger improvement in most cases by not drawing hidden
> tabs.

   ... for those using multiple tabs.

   Simply removing one or two if() probably won't give much of any speedup at 
all though, I think.  At least not on modern CPUs.

-- 
George Staikos
KDE Developer				http://www.kde.org/
Staikos Computing Services Inc.		http://www.staikos.net/