[Beowulf] Nvidia, cuda, tesla and... where's my double floating point?

[Prentice Bisbal]

Perry E. Metzger wrote:
> Prentice Bisbal <prentice at ias.edu> writes:
>> Completely untrue. One of my colleagues, who does a lot of work with GPU
>> processors for astrophysics calculations, was able to increase the
>> performance of the MD5 algorithm by ~100x with about 1.5 days of work.
> 
> That's rather surprising. MD5 is a pure integer algorithm, and is well
> known for being unfriendly to vectorization. There is also extensive
> work by Keromytis et al on the use of GPUs for accelerating
> cryptographic operations, and I don't think they achieved anything
> like that sort of performance improvement.
> 
> I'll point out, by the way...
> 
>> * GPU (single GeForce 8800 Ultra on cylon):
>>    57,640,967.264473 hash/second
> 
> ...that implies moving at least 3.7e9 bytes of data (MD5
> operates on blocks of 64 bytes) into the GPU per second, entirely
> ignoring the 64 Feistel rounds within the GPU. Each round is 4 xors
> and a rotate, and they can't be done in parallel, so we get a total of
> about 1.8e10 integer ops (entirely ignoring the world shuffling) per
> second. That's... rather a lot.
> 
> Perry

Perry,

I was just passing the information along from my colleague. I forwarded
your response to him. Maybe he will reply himself and go into more
detail about his findings for you.

--
Prentice