[Beowulf] Has anyone actually seen/used a cell system?
agshew at gmail.com
Mon Oct 2 08:03:41 PDT 2006
On 10/2/06, Vincent Diepeveen <diep at xs4all.nl> wrote:
> Not wanting to sound too negative, but total nonsense concept.
> First of all this 'sequoia' claims to be a new programming language.
> Meaning it'll take a year or 30 until some good compilers for it are there,
> provided someone is going to support it.
> Which isn't going to happen.
Like many new programming systems, it compiles to C.
> The parallellization basically is based upon complex assumptions for
> programmers. So for programmers they don't actually make it easier than
> trivial parallellization is via C/C++ function calls.
> The sequoia parallellization basically is simplistically over for loops that
> a programmer himself can trivially parallellize too.
Sequoia allows the same source to compile and run on systems with
very different memory hierarchies. It uses MPI on clusters and DMA
on the Cell. It also manages overlays on the Cell. Do you consider a
portable runtime system that manages overlays and streams data
asynchronously trivial to implement?
> Further the optimization of sequoia simply doesn't happen. They assume
> "kernel libraries" solve the problem. Interestingly it mentions explicitly:
> "if kernel libraries could be obtained, such as FFTW and the intel MKL for
> PCs, or the IBM SPE matrix library for Cell, we call these libraries from
> Sequoia leaf tasks".
> In short if some algorithm has not been implemented for sequoia, sequoia is
> unusable. Others may do the work as usual to promote sequoia.
As I understand it, the leaf tasks can be written in C, Fortran, or whatever.
Saying Sequoia is unusable is like saying that MPI is unusable.
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