Author: Aaron Gordon
Date: 08:01:51 09/03/02
Go up one level in this thread
On September 03, 2002 at 10:29:00, Robert Hyatt wrote:
>I already do that. I have about 30 positions that I use during the profile
>stage of "make profile"...
>
>I'm not sure what the -openmp is supposed to do since I am not using any
>of the openMP pre-processing directives for parallel programming...
>
>By the way, I also use -fno-alias since I don't write that kind of sloppy
>code...
>
>I will try the -O3. Last time I did it slowed down just a bit so I stuck
>with -O2...
Ah ok, just wondering. I only see:
CFLAGS='$(CFLAGS) -D_REENTRANT -O2 \
-prof_use -prof_dir ./profile -fno-alias -tpp6' \
in the crafty makefile. I just assumed you used the same on your quad. -O3 may
just depend on which version you're compiling. I had a similar experience.. I
found -O3 was a hair faster so I just stuck with it. I haven't compared it to
-O2 lately. If you find -O3 is slightly slower then I have a lot of recompiling
to do. :)
Also something else I was curious about.. perhaps you'd be able to shed some
insight on. When I was doing the profiling for Slate's dual box I found the
fastest way to make the binaries was by using those settings *BUT* run the SMP
tests on my machine (single CPU). I just profiled with normal settings, exited.
Then I profiled again with smpmt 2 and exited (making two dyn's). After
recompiling it ended up being a good deal faster than when Slate profiled it on
his box using his dual cpus.
I have a guess as to why it could do this but I do not know enough about it to
explain it properly. I'm thinking maybe the way I did it provided a "synthetic"
dual cpu box which operated properly throughout the entire test with two
threads, providing better profiling information. Think that is possible? I think
Slate mentioned something about SMP doing random things, cutting off stuff and
whatnot. I'm not sure if it did that when I profiled but thats why I'm guessing
at this. Otherwise I haven't a clue. :)
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