[gclist] Precise GC's performance

[David Chase]

When you do your benchmarks on the RISC machine, be sure to turn 
up the optimization level as high as possible, and report both the 
flags and the compiler and the version. Also, you should probably 
perform multiple runs, both ways. (If at all possible, read the fine 
manual first.  For Sun, with Sun's compilers, a good thing to say 
is "-fast", perhaps "-fast -xO4" (Solaris) or "-fast -O4" (SunOS)).

I realize that this is onerous and a pain, but it is relatively easy 
to get +/- 20% variation between compilers, compiler flag settings, 
and one run and the next.

What I would expect to see is relatively little difference between 
the two code generation styles at low levels of optimization, and 
much more at higher levels of optimization.

Sorry to be such a nag about this, but paying attention to these 
details will make the difference between dubious numbers, and very 
interesting numbers.  

David