[Raion]

After studying the code of GTK1 and 2, I figured out a major reason why GTK1 and 2 apps are slow on IRIX:

IRIX, and the hardware underlining it do not support hardware accelerated antialiasing, or at least the routines that GTK relies on. Thus, GTK1 and 2 make calls to Cairo and Xrender that allow them to calculate it on the CPU.

I'm no expert here, but this is a major issue with these apps on IRIX from everything that I'm able to see. There's a few approaches we can probably take to optimize this:

1. We write an AA library for IRIX that can shim in and optimize the heck out of that to help get around the problem. 

2. Somehow have Cairo/Xrender bypass these requests and just live without AA. 

This won't resolve the other issues, namely with glib, or the fact that GTK2 especially expects a 32-bit X server with a single colormap, not a 24-bit X server with multiple colormaps. 

Alternatively, we just give up on GTK apps and go for apps using alternative toolkits. I have a sneaking suspicion that QT also uses similar AA routines though. Either way, as someone who thinks it's unacceptable to port an app that only runs on very fast machines, it's a major area of concern for me.