🚀 go-pugleaf

In article <85593@linus.UUCP> bs@gauss.UUCP (Robert D. Silverman) writes:
| Huh? I don't see multiple modulus operations in the loop below. I see ONE.
| How can one modulus operation inside a loop "over-emphasize" integer
| modulus?

Because it occurs at a much higher frequency in this loop than is
"normally" found in most programs.  In our collection of benchmark
programs, out of 50K C lines (85K assembly lines) there were 104
integer division/modulo operations (most were integer division) --
about 0.1%.  This is a static measurement -- I don't have the dynamic
frequency handy, but it is also small.

| :and spends roughly 75% of its time performing the "%" operation.
|  
| This is exactly my point! The fact that one operation takes 75% of the run
| time for a loop with about 20 operations indicates how badly SPARC does
| division. Most programs may not do a lot of division, but when a program
| DOES require it, the performance of the SPARC is a joke.

Not just on SPARC -- it spends this amount of time on many
architectures.  It is very hard to greatly speed up division (although
the TI guys seem to have done it).  Division will usually be slower
than other arithmetic operations by an order of magnitude.

	-- Tim Olson
	Advanced Micro Devices
	(tim@amd.com)