[Numpy-discussion] strange sin/cos performance
Andrew Friedley
afriedle at indiana.edu
Wed Aug 5 11:19:52 EDT 2009
> Is anyone with this problem *not* running ubuntu?
Me - RHEL 5.2 opteron:
Python 2.6.1 (r261:67515, Jan 5 2009, 10:19:01)
[GCC 4.1.2 20071124 (Red Hat 4.1.2-42)] on linux2
Fedora 9 PS3/PPC:
Python 2.5.1 (r251:54863, Jul 17 2008, 13:25:23)
[GCC 4.3.1 20080708 (Red Hat 4.3.1-4)] on linux2
Actually I now have some interesting results that indicate the issue
isn't in Python or NumPy at all. I just wrote a C program to try to
reproduce the error, and was able to do so (actually the difference is
even larger).
Opteron:
float (32) time in usecs: 179698
double (64) time in usecs: 13795
PS3/PPC:
float (32) time in usecs: 614821
double (64) time in usecs: 37163
I've attached the code for others to review and/or try out. I guess
this is worth showing to the libc people?
Andrew
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