[Beowulf] Broadwell HPL performance
hahn at mcmaster.ca
Fri Apr 22 14:17:35 PDT 2016
> cores can stabilize turbo frequencies above nominal clock. The turbo
> boost is more pronounced the less cores you have (less heat).
but is it based on heat or on some internal measure of (instruction) load?
from Intel docs (albeit in earlier generations), the narrative seems to be
that turbo is disabled if you use more than a smallish fraction of the cores.
ie, that you get no turbo at all unless you have several fully-idle cores.
(not sure whether they have to be in HALT, or just a lower power state.)
it would be easier to manage if temperature-based (and superior cooling
would pay off in more time-in-turbo. I'm not clear on whether the
AVX-downclocking thing also might me temperature based. (or perhaps power
> Size LDA Align. Time(s) GFlops Residual Residual(norm) Check
> 90000 90000 4 699.126 695.1769 6.759477e-09 2.983269e-02 pass
nice! and thanks.
More information about the Beowulf