🚀 go-pugleaf

Stephen Knilans (stephenk@netcom.com) wrote:
: In article <dke-2803961851210001@adnline290.adnc.com> dke@adnc.com (David K. Every) writes:
: >In article <4jf32c$qm6@steel.interlog.com>, daveacg@interlog.com (Dave
: >Glue) wrote:
: >
: >> PPC is faster running Bytemarks. That is all that it shows.  Wow,
: >> looking at SpecMarks, the Pro is faster, guess it's the faster
: >> processor then.
: >
: >OK.. but Apple and others have shown that PowerMacs are faster than P5's
: >by a gawd awful amount - up to 3 times at the same clock rate (fp
: >intensive stuff)... now according to Intels OWN numbers, the P6 is only
: >50%+ faster at the same clock rate (at least the ones I saw)... so that
: >would make it what?!?! A heck of a lot slower in the real world than a
: >604?!?!
: >
: >Which seems to be the case I've seen... (only based on the P5's). Intel
: >claimed it was as good as the 601... it was EATEN ALIVE. We did some
: >comparisons and the 66mhz 601 was beating the 120mhz P5 in processor or
: >floating point intesive stuff. So now they claim the P6 is better still...
: >and I'm supposed to beleive what? That THIS TIME they mean it... that they
: >didn't lie (market creatively) like they always do?!?!  I look at the
: >performance difference on my 150mhz 604 (as compared to a 66mhz 601) and
: >think, there is NO WAY that Intel made the P6 3 TIMES faster (minimum)
: >than the P5... which is what they would have had to have done.
: >-- 

: Ya know, I WAS going to mail this post back seperate, but I guess I'll do it 
: HERE!  the P5 was "EATEN ALIVE" by the 601, HUH?  Look at this, and tell me how
: we are mistaken!

: #include <stdio.h>
: #include <math.h>
:  
: void main(void)
: {
: 	double	sum, i;
: 	
: 	sum = 0;
: 	for(i=1;i<10000000;i++)
: 	{
: 		sum = sum + sqrt(sin(i/4.2)*sin(i/4.2) + log(i));
: 	}
: 	printf("total: %f", sum);
: }
: /*** end ***/
: /*  
: And the result is:
:
   
[Result which shows Pentiums blowing away PPC601 deleted]

I didn't want to say anything, because I knew from just looking at the 
code how silly it was. I think that it was hashed out here a while back
that PPC601's didn't support transedentals (sine, cosines) via hardware,
while pentiums did, so any simplified benchmark like the one given by
Mr Hansen will show the Pentium "better" than a PPC chip.  I think that
it's not even close to a decent benchmark, all it shows you is that if
you happen to be writing your own code, and you use a bunch of sines and 
cosines all the time, you'd be better off with a Pentium, that's about it.

Ofcourse Mr Hansen could return with a new program which completely eliminates
sine and cosine, but he could then carefully pick some operations whose
code implementation uses instructions which are faster on the PPC601
than a Pentium.  And then if someone else had the energy or drive to do it,
just come back with a different "benchmark" which could favor the Pentium.
This is why benchmarking is a difficult art.

: Please note, that the first measurement was from GREGORY HANSON, a PPC user!
: The other ones were by ME on a LINUX 1-3.78 system that had SEVERAL processes
: running!  HE listed his system as a PPC601/100 which I ASSUME is a 601 Power
: PC chip CPU running at 100MHZ.  GRANTED, my system has 256K PB cache, but 
: This benchmark is HEAVILY FPU intensive, and should be a good indicator of FPU
: performance.  On an apples to apples comparison(approx = attempts at optimizing)
: the P5/100 was 86% FASTER!!!!!! 

: Either HANSEN was mistaking, I misinterpreted his info, or you have the
: benchmarks BACKWARDS!  This test has a set number of iterations, and so 
: lower numbers are BETTER, as they indicate it took less time to complete.

: Steve

: BTW EACH loop has:

: 3 adds
: 2 divides
: 1 multiply
: 4 transcendentals

: ALL are double precision!