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povray: Revised numbers
- From: Scott Robert Ladd <coyote at coyotegulch dot com>
- To: gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Sat, 17 Jan 2004 16:33:51 -0500
- Subject: povray: Revised numbers
I love live peer review. No, I really do... ;)
If we're going to debate the relative quality of mainline and tree-ssa,
it seems to me we need some real numbers. I'm an engineer, not a fortune
teller.
Here are revised numbers for my povray test, based on comments both
public and private:
compile benchmark
time time
-------- ---------
gcc mainline 1:43 7:59
w/ -mfpmath=sse 1:46 6:30
gcc tree-ssa 1:46 7:35
w/ -mfpmath=sse ** SEG fault **
icc 8.0 1:53 5:50
Previously, I was unaware of the --disable-checking switch; using it to
build tree-ssa improved its compile time such that it performs at the
same speed as mainline.
Someone suggested privately that I try -mfpmath=sse with GCC; I hadn't
had good results with that option on some other code, but I tried it
just to see what would happen.
Mainline's code became *much* faster with -mfpmath=sse; however,
tree-ssa generated a povray that segfaulted during picture generation.
No, I have not had time to see if this is a known bug.
Mainline looks *much* better now; however, much as I want tree-ssa to
move forward, I find myself concurring with many of Mark's views.
I may, if possible, run my Acovea program on GCC with povray, to see if
I can find a set of switches that equal Intel's performance. I suspect,
however, that most of Intel's advantage stems from its vectorization of
code.
--
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing