Kearnstd
Elf Wizard
Premium
join:2002-01-22
Mullica Hill, NJ | reply to espaeth
Re: For those wondering "Why Playstation 3s?"
PS3s really are being used in ways that Sony never intended lol. how long till DARPA builds a supercomputer of 5000 PS3 CPUs lol.
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[65 Arcanist]Filan(High Elf) Zone: Broadband Reports |
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Steve
I'm a PC, so shut up
Consultant
join:2001-03-10
Yorba Linda, CA
| reply to TSI Gabe
said by TSI Gabe  :No Actually removing a printf simply displaying the value being calculated completely removed the md5 function from the code. The compiler did what it was supposed to do: if you were calling a function that had no side effects, it knew that it could eliminate the call without having any effect on correct operation. It was right.
Benchmarking is a known science; calling your operation in a way that insists on a side effect (as I'm sure you found) lets you get the effect you want.
Steve
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Stephen J. Friedl | Unix Wizard | Microsoft Security MVP | Orange County, California USA | my web site |
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TSI Gabe
Premium,VIP
join:2007-01-03
Chatham, ON | reply to Steve
No Actually removing a printf simply displaying the value being calculated completely removed the md5 function from the code. |
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Steve
I'm a PC, so shut up
Consultant
join:2001-03-10
Yorba Linda, CA
| reply to TSI Gabe
said by TSI Gabe :That was the C compiler optimizing my code into doing nothing quite literally. Sometimes those C optimizations don't really help... It's far more likely that your optimizer found a bug in your code than you found a bug in the optimizer.
The problem with compilers is that they do exactly what you ask them too bad women and children won't follow that example 
Steve
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Stephen J. Friedl | Unix Wizard | Microsoft Security MVP | Orange County, California USA | my web site |
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TSI Gabe
Premium,VIP
join:2007-01-03
Chatham, ON | reply to Steve
That was the C compiler optimizing my code into doing nothing quite literally. Sometimes those C optimizations don't really help... |
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beaups
join:2003-08-11
Hilliard, OH | reply to Steve
lol I was just wondering the same thing |
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Steve
I'm a PC, so shut up
Consultant
join:2001-03-10
Yorba Linda, CA
| reply to TSI Gabe
said by TSI Gabe :Yeah I've coded an MD5 algo myself for the PS3 and it does 80 million hashes per second. What ever happened to 30 billion hashes per second?
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Stephen J. Friedl | Unix Wizard | Microsoft Security MVP | Orange County, California USA | my web site |
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TSI Gabe
Premium,VIP
join:2007-01-03
Chatham, ON | reply to espaeth
Yeah I've coded an MD5 algo myself for the PS3 and it does 80 million hashes per second.
This may not look like a lot, but its just about as much as a very expensive Xeon server so your bang for the buck is quite real. |
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espaeth
Digital Plumber
Premium,MVM
join:2001-04-21
Minneapolis, MN | There's a nice overview here: »people.csail.mit.edu/tromer/slid···rump.pdf |
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