Hi guys,
I've been messing with the drivers in Linux and created an anomaly ( at least i think it is that ). When active OpenCl allows me to employ both Devastator and Pitcairn GPU's. This is great because i can run long running kernels on Pitcairn while Devastator takes care of the GUI or whatever else i decide to do with it. Curiously Catalyst Control Center reports problem with the driver and refuses to run.
Later i made a clean install to replicate this effect and nothing i try to do gets me to the same behavior. It's back to the normal state where CCC decides which GPU can be used and which doesn't appear on the platform list. Which is the intended behavior on laptops with crossbar switch.
This sums up the strange behavior :
- OpenCL device [ 0 ] -> CL_DEVICE_TYPE_GPU :: Devastator
- OpenCL device [ 1 ] -> CL_DEVICE_TYPE_GPU :: Pitcairn
- OpenCL device [ 2 ] -> CL_DEVICE_TYPE_CPU :: AMD A10-4600M APU with Radeon(tm) HD Graphics
Driver version reported, however i suspect swapping drivers back and forth between { 12.8, 12.10, 13.1 } and also SDK 2.6 -> SDK 2.8 made some mess and i got a hybrid monstrosity. : ]
- OpenCL device [ 1 ] -> clGetDeviceInfo ( CL_DRIVER_VERSION ) : 1016.4 (VM)
- OpenCL device [ 1 ] -> clGetDeviceInfo ( CL_DEVICE_VERSION ) : OpenCL 1.2 AMD-APP (1016.4)
- OpenCL device [ 1 ] -> clGetDeviceInfo ( CL_DEVICE_MAX_COMPUTE_UNITS ) : 0 <- incorrect value, should be 20 for Pitcairn
Also another curious thing, my benchmark code running on this "defective setup" runs correctly at ~0.3 seconds, while driver 13.1 needs ~1.3 seconds !
Whatever is happening seems to be beneficial and extremely useful for APU plus GPU users. I will report my findings, in the meantime i welcome any ideas.
Greetings,
icosahedron
