DCACHE_SIZE

Message

Tyx · #1 Post by **Tyx** » Wed Nov 08, 2006 12:00 pm

Maybe this has been asked before, but how does one find the optimal DCACHE_SIZE value? For linux on P4 systems, the default makefile says
12000 for the serial and 4000 for the MPI version... How can I determine the
correct value for DCACHE_SIZE for my system? Or are these values correct for
every linux system? I saw somewhere that for the serial version at least, using
Jurgen Furthmuller's fft, DCACHE_SIZE should be increased to 16000.

Any comments are welcome.
Thanks
<span class='smallblacktext'>[ Edited ]</span>

tjf · #2 Post by **tjf** » Thu Nov 09, 2006 1:42 pm

While there's probably a well defined theoretical optimum for each architecture/CPU/chipset, it's hard to go past the suck it and see approach. (You don't get something for nothing. You'll have to do some work to get the benefit.)

Take a typical sized problem that you'll be working on and run it on your machine with executables compiled with different cache size parameters. Use the fastest!

Tyx · #3 Post by **Tyx** » Fri Nov 10, 2006 2:37 pm

I suspected as much. Oh well. Thanks

bandy · #4 Post by **bandy** » Tue Nov 14, 2006 7:40 pm

Hi, you can find cache size in /proc/cpuinfo

Did you mean this?