mpn_mul is embarrassingly slow
nisse at lysator.liu.se
Wed Apr 25 11:34:44 UTC 2018
tg at gmplib.org (Torbjörn Granlund) writes:
> More embarrassments. :-)
> I ran some timing tests without my proposed change and with the squqring
> exception code still there. Please consider the following two
> measurements for doing n x 19 limb (first table) and n x 20 limb
> MUL_TOOM22_THREASHLD is 20 for this machine (compiled in, but also
> measured now). My comments below.
For n x 20, n pretty large, what strategy does mpn_mul use? I would
expect repeated toom32, but maybe that gives too much overhed. It seems
we don't have any MUL_TOOM32_TO_BASECASE threshold?
Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677.
Internet email is subject to wholesale government surveillance.
More information about the gmp-devel