In message from "Li, Bo" <[EMAIL PROTECTED]> (Wed, 27 Aug 2008 08:50:11
+0800):
Hello,
IMHO, it is better to call the BLAS or similiar libarary rather than
programing you own functions.
Eh, I would be happy to use GPGPUs only via math libraries - it's
equal for me to "black box" as Vincent said. But this libraries are
too restricted for our purposes.
And CUDA treats the GPU as a cluster,
so .CU is not working as our normal codes. If you have got to many
matrix or vector computation, it is better to use Brook+/CAL, which
can show great power of AMD gpu.
There is 2 possible interpretations of your word "better".
1) Brook+/CAL gives more high performance or price/performance etc
than Nvidia (hard+software)
or
2) It's simpler to program using Brook+/CAL.
What is the right interpretation ? BTW, is in necessary to use Brook+
w/CAL - or I may write the program using Brook+ WITHOUT using (and
detailed knowledge) of CAL ?
I.e. I want to write the "subroutine" on brcc, compile and then link
w/fortran program using some gcc function as a "wrapper" (for
organizing of interface to fortran).
Yours
Mikhail
Regards,
Li, Bo
----- Original Message -----
From: "Mikhail Kuzminsky" <[EMAIL PROTECTED]>
To: "Vincent Diepeveen" <[EMAIL PROTECTED]>
Cc: "Beowulf" <beowulf@beowulf.org>
Sent: Wednesday, August 27, 2008 2:35 AM
Subject: Re: [Beowulf] gpgpu
In message from Vincent Diepeveen <[EMAIL PROTECTED]> (Tue, 26 Aug 2008
00:30:30 +0200):
Hi Mikhail,
I'd say they're ok for black box 32 bits calculations that can do
with
a GB or 2 RAM,
other than that they're just luxurious electric heating.
I also want to have simple blackbox, but 64-bit (Tesla C1060 or
Firestream 9170 or 9250). Unfortunately the life isn't restricted to
BLAS/LAPACK/FFT :-)
So I'll need to program something other. People say that the best
choice is CUDA for Nvidia. When I look to sgemm source, it has about
1
thousand (or higher) strings in *.cu files. Thereofore I think that
a
bit more difficult alghorithm as some special matrix
diagonalization
will require a lot of programming work :-(.
It's interesting, that when I read Firestream Brook+ "kernel
function"
source example - for addition of 2 vectors ("Building a High Level
Language Compiler For GPGPU",
Bixia Zheng ([EMAIL PROTECTED])
Derek Gladding ([EMAIL PROTECTED])
Micah Villmow ([EMAIL PROTECTED])
June 8th, 2008)
- it looks SIMPLE. May be there are a lot of details/source lines
which were omitted from this example ?
Vincent
p.s. if you ask me, honestely, 250 watt or so for latest gpu is
really
too much.
250 W is TDP, the average value declared is about 160 W. I don't
remember, which GPU - from AMD or Nvidia - has a lot of special
functional units for sin/cos/exp/etc. If they are not used, may be
the
power will a bit more lower.
What is about Firestream 9250, AMD says about 150 W (although I'm
not
absolutely sure that it's TDP) - it's as for some
Intel Xeon quad-cores chips w/names beginning from X.
Mikhail
On Aug 23, 2008, at 10:31 PM, Mikhail Kuzminsky wrote:
BTW, why GPGPUs are considered as vector systems ?
Taking into account that GPGPUs contain many (equal) execution
units,
I think it might be not SIMD, but SPMD model. Or it depends from
the software tools used (CUDA etc) ?
Mikhail Kuzminsky
Computer Assistance to Chemical Research Center
Zelinsky Institute of Organic Chemistry
Moscow
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