hardware for GEMM_MULTITHREAD_THRESHOLD=4

[jeromerobert]

I would like to use GEMM_MULTITHREAD_THRESHOLD in ger.c and ztrmv.c. The threshold depends on the hardware. The faster is the CPU the higher the threshold should be. I have several PCs available some are slow, some other are recent Xeon. I would like to know on which PC I should calibrate the threshold to be coherent with other GEMM_MULTITHREAD_THRESHOLD in OpenBLAS.

In other word, on which hardware did you calibrated the existing GEMM_MULTITHREAD_THRESHOLD usage ?

May be this should be added to the Makefile.rules file.

[jeromerobert]

From #216 and #103 I understand it should be a SandyBridge. That's precise enough for me chose the machine for a calibration.