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From kiran lonikar <loni...@gmail.com>
Subject Re: Code generation for GPU
Date Sat, 12 Sep 2015 12:59:54 GMT
Thanks. Yes thats exactly what i would like to do: copy large amounts of
data to GPU RAM, perform computation and get bulk rows back for map/filter
or reduce result. It is true that non trivial operations benefit more. Even
streaming data to GPU RAM and interleaving computation with data transfer
works but it complicates the design and doing it in spark would be even
more so.

Thanks for bringing out the sorting. Its a good idea since its already
isolated as you pointed out. I was looking at the terasort effort and
something I always wanted to take up. But somehow thought expression would
be easier to deal with in a short term. Would love to work on that after
this especially because unsafe is for primitive types and suited for GPUs
computation model. It would be exciting to better the terasort record too.

Kiran
On 10-Sep-2015 1:12 pm, "Paul Wais" <paulwais@gmail.com> wrote:

> In order to get a major speedup from applying *single-pass*
> map/filter/reduce
> operations on an array in GPU memory, wouldn't you need to stream the
> columnar data directly into GPU memory somehow?  You might find in your
> experiments that GPU memory allocation is a bottleneck.  See e.g. John
> Canny's paper here (Section 1.1 paragraph 2):
> http://www.cs.berkeley.edu/~jfc/papers/13/BIDMach.pdf    If the per-item
> operation is very non-trivial, though, a dramatic GPU speedup may be more
> likely.
>
> Something related (and perhaps easier to contribute to Spark) might be a
> GPU-accelerated sorter for sorting Unsafe records.  Especially since that
> stuff is already broken out somewhat well-- e.g. `UnsafeInMemorySorter`.
> Spark appears to use (single-threaded) Timsort for sorting Unsafe records,
> so I imagine a multi-thread/multi-core GPU solution could handily beat
> that.
>
>
>
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