Date: Wed, 22 Dec 1999 23:53:13 +0100 (CET) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-stable@FreeBSD.ORG Subject: Re: AMD 3DNow instructions on FreeBSD Message-ID: <199912222253.XAA16064@dorifer.heim3.tu-clausthal.de>
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Sean-Paul Rees wrote in list.freebsd-stable:
> Is there a MMX enabled setiathome for us with non-3DNow! enhanced
> processors?
No, MMX is completely useless for this kind of stuff, because
MMX does not support floating point operations. Sorry.
However, I modified the FFT algorithm to optimize memory
throughput, at the cost of memory footprint (it needs about
2 Mbyte more RAM). The speed increase is not as impressive
as with the 3DNow version, but it's still significant.
Here are some numbers:
Dual Celeron-466, Gigabyte 6BXD mainboard:
original code: 18.0 - 18.5 hours per CPU
generic optimized code: 10.5 - 11.0 hours per CPU
speed increase: ~ 40%
Single Celeron-333, Asus P2B mainboard:
original code: 14.0 - 14.5 hours
generic optimized code: 10.5 - 11.0 hours
speed increase: ~ 25%
Single Pentium-II-450, Asus P2B-LS mainboard:
original code: 9.0 - 9.5 hours
generic optimized code: 7.5 - 8.0 hours
speed increase: ~ 16%
As you can see, the Dual Celeron benefits the most, because
it has a very weak RAM bandwidth, but fast (though small)
L2 cache.
AMD K7-500, MSI MS6167 mainboard:
original code: 10.0 - 10.5 hours
Athlon optimized code: 4.0 - 4.5 hours
speed increase: ~ 60%
These numbers speak for themselves. 3DNow rules. :)
I'm still waiting for a response from the Seti@home folks.
They have all the code, but they seem to ignore it.
Regards
Oliver
--
Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany
(Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
"In jedem Stück Kohle wartet ein Diamant auf seine Geburt"
(Terry Pratchett)
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