how can i use all power of my cpus?

[hjl150505]

my machine have 12 cpus, when i use the two matrixs A and B for the function cblas_sgemm(), i found it will call the function GEMM_LOCAL(args, range_m, range_n, sa, sb, 0) which in the driver/level3/level3_thread.c. I found if i modified SWITCH_RATIO which in the param.h from 4 to 0, it will call the function gemm_driver(args, range_m, range_n, sa, sb, 0) which in the dirver/level3/level3_thread.c too.
The question is: when i run the code which use openblas the cpu utilization have improve， but it will failed final. shouldn't i modified the SWITCH_RATIO from 4 to zero? If not, how can i improve the utilization of my cpu except use USE_SIMPLE_THREADED_LEVEL3 = 1.

[hjl150505]

when i use gdb to debug my program, i receive this:
Program received signal SIGSEGV, Segmentation fault.
sgemm_beta () at ../kernel/x86_64/gemm_beta.S:122
MOVSD %xmm0, 0 * SIZE(C1)

how can i solve this problem

[martin-frbg]

I would not dare to meddle with internal constants like that, in particular ones that only have one particular value whereever they are defined at all. :-)
Can you provide more context - what CPU model (actually 12 cpus, or a 12-core cpu ?), what size are the matrices A and B (typically), are you using a current version of OpenBLAS ?
(With current OpenBLAS and Intel CPUs you could try the suggestions in #923 )

[hjl150505]

The environment compile openblas is msys&mingw-w64. I want to use openblas in windows.
1、It is 12-core cpu
2、the matrices size is:
M = 12
N = 100000
K = 128
3、 the openblas version is 0.2.19.dev

i want use mult-thr

eads, but it is only one thread running. So i change SWITCH_RATIO = 4 in param.h to SWITCH_RATIO = 0, when i use gdb to debut my program i get this error: