Subject: Re: [linux-audio-dev] Athlon/3dnow! dsp benchmark results
From: Benno Senoner (sbenno_AT_gardena.net)
Date: ma syys 06 1999 - 08:21:56 EDT
Hi folks,
I can't wait go get such a beast like the Athlon.
:-)
Eric: are you sure that the biquad filter is coded in an optimal way.
Maybe you have to reorder things ?
I can't believe that 3Dnow is slower than optimized C on the Athlon.
But it's nice to see that well optimized C code runs only 30% slower than
3dnow code.
:-)
regards,
Benno.
On Mon, 06 Sep 1999, est_AT_hyperreal.org wrote:
> I coded a biquadratic filter in C, bummed C (`caching' values in
> locals csound-style), and 3dnow. I tested how long it took (in
> microseconds) to process a buffer of 128 mono float samples 100 times.
>
> I also wrote another routine to mix two channels into one with scale
> factors for each input channel. I ran it on the same size data as the
> biquad benchmark.
>
> On my amd k6-2/350 using gcc-2.95.1, I got the following typical results:
>
> biquad 3dnow: 382
> biquad gcc: 2004
> biquad bummed gcc: 1493
> mix 3dnow: 105
> mix gcc: 659
>
> Dieter Nuetzel was kind enough to run the same tests on his Athlon/500
> system with pgcc-2.91. The results he got were:
>
> biquad 3dnow: 573
> biquad gcc: 679
> biquad bummed gcc: 340
> biquad gcc (-O6 -mpentiumpro): 378
> biquad bummed gcc (-O6 -mpentiumpro): 353
> mix 3dnow: 64
> mix gcc: 136
> mix gcc (-O6 -mpentiumpro): 99
>
> As you can see, biquad/3dnow was actually slower on his system! mix
> allowed 3dnow to maintain a (diminished) lead on the Athlon. It's
> more inherently SIMD. In the case of biquad I think 3dnow beat gcc on
> the k6-2 because the k6-2 fp architecture is just way behind 3dnow.
> In the Athlon it's leap-frogged ahead. Apparently the 3dnow
> instructions have higher latency on the Athlon. I have no idea
> whether AMD plans to fix this.
>
> Lastly, the Athlon is fast. :)
>
> Eric
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