From: Kyle Schmitt <kyleaschmitt@...>
Date: 2008-02-21T04:33:12+09:00
Subject: Re: [QUIZ #157] 32bit vs 64bit vs UML performance

Err wait, the way you phrased your benchmarks is a bit confusing, post
the total time for each by bitness(32 or 64) by cpu.

As for the intel x86-64 issue, it's become fairly well known that the
32 bit execution time is faster than the 64.  With the AMD 64 bit
boxes it greatly depends on the application being run, sometimes 32 is
faster (but not as drastically as in the intel world), but more often
64 is faster.

If you're really interested in squeezing every last living ounce out
of your box, you may want to fine-tune those x86-64 compilation
settings, and you'll probably have to benchmark & test for oft used
libraries and binaries, but use common sense (recompiling ls & tar
won't get you much, but zlib & gzip may help a bit).

One final thing, when benchmarking, it may suck to wait for many runs
to go by, but you really need to do more than two runs :)
You probably already know all this, but still, for passers by, drop to
single user mode if possible, make sure no extra processes are
running, and run the test as many times as you can.  Maybe that's
four, but hopefully it's twenty, or a hundred.

--Kyle