xianyi/OpenBLAS — Issue #79: performance of dgemm(500x2, 2x2)
Author: JeffBezanson
Created: 2012-02-23 20:40:06+00:00
State: open

I see a significant performance gap between openblas and mkl in this case:

Julia, using openblas:
```
julia> a=rand(500,2)
julia> b=rand(2,2)
julia> @time for i=1:10000; a*b; end
elapsed time: 0.08133101463317871 seconds
```

Matlab, using MKL:
```
>> tic();for i=1:10000,a*b;end;toc()
Elapsed time is 0.025024 seconds.
```

As far as I can tell from CPU use, MKL is not using multiple threads here, so that's not the issue.
I don't know whether it's possible to fix this, but it would be great.