🚀 go-pugleaf

In article <28594@amdcad.AMD.COM> tim@amd.com (Tim Olson) writes:
:In article <34058@mips.mips.COM> mash@mips.COM (John Mashey) writes:
 
:| 	I'm always nervous about micro-level benchmarks.  Now, I hate to have
:| 	to defend SPARC :-), but I must: realistic integer benchmarks
:| 	that I know [like the SPEC ones] simply don't correlate with
:| 	the results claimed below, at least not very much.
:| 	The RISC machines are noticably faster on actual integer programs....
:
:The benchmarks over-emphasize integer modulus.  For example, the
 
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?

:benchmark that reportedly tests register-integer variables looks like:
:
:/* benchreg - benchmark for  register  integers 
 
Some code deleted. It contains a loop with perhaps 20 arithmetic operations
inside it. Only 1 involves division (and/or remainder). Here's the loop contents:

:                for (c = 1; c <= 40; ++c)
:                        {
:                        a = a + b + c;
:                        b = a >> 1;
:                        a = b % 10;
:                        m[a] = a;
:                        b = m[a] - b - c;
:                        a = b == c;
:                        b = a | c;
:                        a = !b;
:                        b = a + c;
:                        a = b > c;
:                        }
: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.
-- 
Bob Silverman
#include <std.disclaimer>
Internet: bs@linus.mitre.org; UUCP: {decvax,philabs}!linus!bs
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