OpenMathLib / OpenMathLib/OpenBLAS
Above average kernel times causing slow performance
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- Dominant language
- C
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Description
Hi!
In comparing OpenBLAS performance with Intel MKL I've noticed that (at least in my particular case: real or hermitian eigenvalue problem, e.g. ZHEEV) OpenBLAS is consuming too much more kernel times (red bars in htop) than Intel MKL and maybe this is why it is so slow (three to five times slower, depending on matrix size) compared to MKL. Does anybody know what is causing so much kernel threads/time and how to avoid it? I've already limited OPENBLAS_NUM_THREADS to 4 or 8... TIA.
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Research direction
Start by reproducing the ZHEEV real or Hermitian eigenvalue comparison against Intel MKL, using the reported OPENBLAS_NUM_THREADS limits and observing kernel time in htop. Trace the relevant OpenBLAS execution and threading behavior; done means identifying the cause of the slowdown and a validated way to avoid it.
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Assessment
- Tech stack
- c
- Domain
- performance
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 20/100