[viff-devel] [issue75] Test without local computations

[Martin Geisler]

Hi everybody,

I've done some tests where I replaced the normal FieldElement class
with a new class named FakeFieldElement (rev 464008ada9c2). This class
fakes all computations by always returning 1.

Timing 10000 multiplications using the real and the fake field
elements give these results between three machines on the DAIMI LAN:

  +-------------------+----------+----------+------+
  | Field size (bits) | Real (s) | Fake (s) | Diff |
  +-------------------+----------+----------+------+
  |         50        |   14.1   |   13.5   |  4%  |
  +-------------------+----------+----------+------+
  |        100        |   14.3   |   13.2   |  8%  |
  +-------------------+----------+----------+------+
  |        200        |   14.5   |   13.3   |  8%  |
  +-------------------+----------+----------+------+
  |        400        |   15.0   |   13.1   | 13%  |
  +-------------------+----------+----------+------+
  |        800        |   16.2   |   13.3   | 18%  |
  +-------------------+----------+----------+------+
  |       1600        |   21.4   |   13.5   | 37%  |
  +-------------------+----------+----------+------+

The results show that there is something to improve for large numbers,
but for field of size 50-100 bit the difference is quite small. It
would be interesting to see how the numbers compare when Sigurd
finishes the patch for using GMPY:

  http://tracker.viff.dk/issue10

It is currently waiting for a reply on my review comments.

These results are from a gigabit LAN, so the time spend on network
communication is as low as it can possible get. I guess that means
that the rest of the time is lost in the overall machinery :-(

-- 
Martin Geisler