What to do with a K6-2?
 

I have been given a 550MHz AMD K6-2 with 64MB memory, but it seems very slow for the projects I am currently working on: my 400MHz P2 is much faster for everything except PSP sieving, where it is about equal.

Does anyone know of a project that will make use of this machine, maybe something with a client that uses the 3DNow! instructions?

You could join [URL=http://www.mersenneforum.org/forumdisplay.php?f=50]Operation Billion Digit[/URL] over in the LMH section of the forum. There are some Pentium Pro's and such working onthe project.

[URL=http://home.earthlink.net/~elevensmooth/Billion.html]English home page for OBD[/URL]

Call me biased :smile: , but when PSP sieving works quite optimally on the K6-2, it seems to be a good candidate.

I think Tony Forbes' MFAC runs quite well on K6-2. He coordinates a search for factors of MM61, see [url]http://www.ltkz.demon.co.uk/ar2/mm61.htm[/url]

Alex

[QUOTE]Call me biased :smile: , but when PSP sieving works quite optimally on the K6-2, it seems to be a good candidate.[/QUOTE]
I will do PSP sieving unless I find something that is better suited. The proth_sieve program has a CMOV optimisation which the P2 can use but the K6-2 can't, I guess that accounts for the difference.

[QUOTE]You could join Operation Billion Digit over in the LMH section of the forum. There are some Pentium Pro's and such working onthe project.[/QUOTE]
That project doesn't really appeal to me, too long term :-)

[QUOTE]I think Tony Forbes' MFAC runs quite well on K6-2. He coordinates a search for factors of MM61, see [url]http://www.ltkz.demon.co.uk/ar2/mm61.htm[/url][/QUOTE]
I would like to try that project, but the link to the linux client is down. Can you point me to another one?

[QUOTE=geoff]I will do PSP sieving unless I find something that is better suited. The proth_sieve program has a CMOV optimisation which the P2 can use but the K6-2 can't, I guess that accounts for the difference.[/QUOTE]

AFAIK, cmov optimizations give you ~5% extra speed. I'd suspect the faster L2 cache of the P2 to have a major impact.

I timed some typical work from a few different projects using a 550MHz K6-2 and a 400MHz P-II. Both machines have 64Mb PC-100 SDRAM and (unused) onboard video, the P-II has 512k L2 cache but I don't know how much the K6-2 has (every program I have tried reports it as 'unknown')

'Ratio' is the P-II time divided by the K6-2 time for the same work.

[CODE]
Project Software Ratio
------------------------------------------------------
LMH (TF below 2^64) mprime 23.9 0.40
ECMNET (ECM on 2+ table) mprime 23.9 0.48
ECMNET (ECM on 2LM table) gmp-ecm 5.0.3 0.99
PSP (sieving) proth_sieve 0.42 0.95
Fermat trial factoring fermat 1.6 1.04
MM31 trial factoring MFAC 2.29 1.35
[/CODE]
gmp-ecm and fermat both use libgmp, I compiled a processor specific version for each machine. The MFAC time is based on the sample MM31 range in the instructions, I'm not sure yet how typical that is.

[QUOTE=geoff]...but I don't know how much the K6-2 has (every program I have tried reports it as 'unknown')...[/QUOTE]
[url]http://www.sandpile.org/impl/k6.htm[/url]

The K6-2's L2 is on the motherboard... I have no idea how to query it...

[QUOTE=Xyzzy]The K6-2's L2 is on the motherboard... I have no idea how to query it...[/QUOTE]
a) Look at the hardware spec table, shown just before the OS starts (at least on my Pentium I system there is shown the cache size in that table); or

b) If you know the motherboard model, you could find its specification on the internet; or

c) Open the case and count the cache chips - there should be written their capacity on them.

[QUOTE=geoff]That project doesn't really appeal to me, too long term :-)[/QUOTE]

Perhaps we should expand to more numbers. I can find out some more and fctor them to 60.

Or perhaps you could do the 64s.