Re: performance improvements for floating point random number generation

[Paul E Johnson]

"Marcus G. Daniels" wrote:
> 
> The optimizations are in today's snapshot and in today's DLLs:
> 
>    ftp://ftp.swarm.org/pub/swarm/src/testing/swarm-2001-04-17.tar.gz
> 
>    ftp://ftp.swarm.org/pub/swarm/binaries/w32/latest
> 
> Thank you, Paul!

Ah, shucks, it wasn't nothin' but a bunch of heavy lifting and blind
poking into dark places....

Here are the RPMs.

base package:
http://lark.cc.ukans.edu/~pauljohn/Swarm/Swarm-2.x_RPMSforRH7/i686/swarm-hdf5-2.1.64.20010417-1.RH7.jdk13.i686.rpm

addon for JDK users:
http://lark.cc.ukans.edu/~pauljohn/Swarm/Swarm-2.x_RPMSforRH7/i686/swarm-hdf5-jdk-2.1.64.20010417-1.RH7.jdk13.i686.rpm

static package for profiling as well as static compilation of swarm
programs:
http://lark.cc.ukans.edu/~pauljohn/Swarm/Swarm-2.x_RPMSforRH7/i686/swarm-hdf5-static-2.1.64.20010417-1.RH7.jdk13.i686.rpm

One new thing I learned is this. If you compile an objective-c program
with the static package installed and with the make flag
EXTRALDFLAGS=-static, it can speed up some shorter programs pretty
dramatically. It makes a much bigger executable, but in some of the time
tests on the random number test program I made, a one-minute program
that just drew random numbers would get 20% or more faster with the
static compilation.  If your program is doing something more than random
numbers, you won't see such a fast improvement, of course.  But, if you
are building a program to run in batch, over and over, the static
version seems like the way to go.

Oh, another thing. The speedup I observe is greater on slower machines. 
More noticable on a PII-400 than a PIII-700.  The 10% figure is obtained
on a PIII-667.  Go figure.

-- 
Paul E. Johnson                       email: address@hidden
Dept. of Political Science            http://lark.cc.ukans.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700

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