open cl mode crashes frequently

[taurus]

I'm currently working on a hires animation (3840x1632) in opencl mode. the rendering speed is great on my old radeon 5770, but it crashes more and more frequently. after ~3-50 rendered frames,mandelbulber freezes or is terminated. Started from a command prompt it outputs on termination the following

Code:

---------- index: 587 -------------
Distance = 6,267516e-002
alpha = -3,628737, beta = 0,018982
x = 5,48362038, y = 2,33623832, z = 2,27177413
OpenCL rendering
ERROR: ComamndQueue::enqueueNDRangeKernel()  (-5)

the freeze remains silent.
Maybe you can use for debugging

[Buddhi]

I think I know what could cause the problem. Error 5 means CL_OUT_OF_RESOURCES. Try to decrease OpenCL / Processing cycle time to e.g. 0.5 s. Then the program will use less GPU memory (will work with smaller queues). Let me know if it helps.

[taurus]

OMG 
Seems, that I caused the problem myself. After my first tests I realized, that slightly increasing the cycle time, reduces the rendertime significantly (I used 4s). I never questioned my settings, cause it went through the preview session in just one night. Yesterday, I tried 3s with full resolution - same problem after less than 20 frames. today i kicked off the rendering with 2s and who wonders, just stopped it after rendering 160 frames today - no problem at all! 
I swear, that I try default setup first, before reporting "bugs" next time...

Thanks Buddhi for getting me back on the right track

[Buddhi]

This what I proposed is only a workaround. In 1.18 I'm, trying to add automatic checking of available GPU memory, but unfortunately under win32 OpenCL library returns zeros instead of avail memory size. Under Linux it works perfect. It limits job size to safe value. 

[taurus]

I'm ok with checking by trial and error, especially because different projects seem to have different optimal settings (see below)
The speed up by higher values is pretty intense, so it is worth the effort, to go to the edge.

>edit
ok, the speedup is not as hot as I had in mind
just checked a frame of my animation (@1920) with cycle times of:
1s > 109,47s
2s > 102,25s
4s >  98,36s
that's a speedup of around 7% between 1 and 2s  and 11% between 1 and 4s.
One crash can blow your speedup to dust...