Re: Performance hit with --enable-atomic-refcount

[Daniel J Sebald]

On 06/06/2014 12:40 PM, Rik wrote:
> 6/6/14
>
> All,
>
> > From the previous benchmarking, there was a doubling in execution time from
> 3.8.1 to the gui-release branch for a nested for loop.  It turns out that
> this doubling is 100% correlated with using the --enable-atomic-refcount
> option to configure.  I built the gui-release branch with this feature
> disabled and the results are then equivalent to the 3.8.1 release.  It
> seems like we need to explore a different solution than this configure
> option so that we can both use Qt graphics and have reasonable performance.

The attomic reference count is, from what I understand, needed for the 
QtHandles code, which implements script callbacks (I say "script 
callbacks" to differentiate from source code callbacks).  Atomic 
reference isn't needed for Qt graphics without that.

However, I believe the atomic reference count can be eliminated with a 
well-organized bi-directional interface between UI/worker threads rather 
than using source-code callbacks.  This could make a good topic for 
OctConf '12.

Dan