great job with multithreaded programs
Stephen Montgomery-Smith
stephen at math.missouri.edu
Tue Jul 3 00:51:16 UTC 2007
I did a recent upgrade of current, and a multithreaded program which
used to take 33s suddenly takes 18s. Somebody did something very right!!!
I can provide details (but please email me directly as I don't subscribe
to current), but basically the program does these massively large 3D
Fourier transforms using the math/fftw3 port. I have two dual Xeon's
with HT running, and I run fftw3 with 4 threads. I use the ULE
scheduler, and have witness and invariants all switched off.
I should add, perhaps disappointingly, that this now only brings FreeBSD
on par with Linux with respect to this program - Red Hat Linux also ran
this at 18s. But hopefully this is part of some rather skillful
reworking of multithreading on FreeBSD and we will see great gains in
the future.
Best regards, Stephen
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