Re: [MLUG] Anyone got a fast modern computer

[Stephen Montgomery-Smith <EMAIL:PROTECTED>]

Thanks, I appreciate it.

Look at the output of the 3rd program - it spent more time on sys than 
user!  Probably means that the multiple multithreading creates more work 
than it saves!  Probably copying cache from one core to another!

And the output of the 4th program - it looks like the computer usage was 
about 1000%!  That's not bad.  Although the timings aren't great.  Maybe 
that would run about as well with fewer threads - who knows.

Thanks for doing this.

By the way, if your machine is really a nocona machine, then 
-march=native means the same thing.  Nevertheless, I do suspect that in 
this arena that the more modern compilers really have made dramatic 
improvements, even if no -march is used.  (For the lurkers, -march 
specifies the architecture.)

Adam Procter wrote:
> This is on the CS department's 16-core Linux server (I don't know all 
> the details of the machine's specs, but I think it has four quad-core 
> Xeons of some sort, 2.8GHz). Note that I compiled with an ancient 
> version of gcc, 3.4.6, and no -march flag of any kind -- so the results 
> were not very good. gcc 4.1 is also on this machine, so I'm going to 
> give that a try with -march=nocona, then see if I can build a newer 
> version of gcc4 in my user space to give -march=native a whirl.
> 
> Adam
> 
> 
> 
> [EMAIL:PROTECTED spherical-1.15]$ gcc -v
> Reading specs from /usr/lib/gcc/x86_64-redhat-linux/3.4.6/specs
> Configured with: ../configure --prefix=/usr --mandir=/usr/share/man 
> --infodir=/usr/share/info --enable-shared --enable-threads=posix 
> --disable-checking --with-system-zlib --enable-__cxa_atexit 
> --disable-libunwind-exceptions --enable-java-awt=gtk 
> --host=x86_64-redhat-linux
> Thread model: posix
> gcc version 3.4.6 20060404 (Red Hat 3.4.6-9)
> [EMAIL:PROTECTED spherical-1.15]$ cat record.txt
> parameters-dd.txt
> 
> real    4m11.133s
> user    4m42.881s
> sys     10m55.899s
> parameters-ft100.txt
> 
> real    1m12.220s
> user    2m24.437s
> sys     4m13.029s
> parameters-ft.txt
> 
> real    1m17.557s
> user    0m50.644s
> sys     5m7.477s
> parameters-jef.txt
> 
> real    75m50.161s
> user    728m55.295s
> sys     44m17.430s
> parameters-mj.txt
> 
> real    4m13.495s
> user    4m46.861s
> sys     11m18.442s
> 
> 
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