[tahoe-dev] disabling optimized assembly in pycryptopp

[Zooko O'Whielacronx]

Folks:

As discussed on this ticket --
https://tahoe-lafs.org/trac/pycryptopp/ticket/85 -- and on IRC, I'm
changing pycryptopp so that it uses the C++ implementations and not
any assembly implementations. This will mean a tiny performance
penalty which nobody will notice since there are major performance
problems in the Tahoe-LAFS protocol itself
(https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance).

Here some benchmark results from the buildbot showing that with asm
disabled, AES and Salsa20 take around twice as long as before (on this
particular box):

Before:

https://tahoe-lafs.org/buildbot-pycryptopp/builders/Kyle%20OpenBSD-amd64/builds/125/steps/bench/logs/stdio

With CRYPTOPP_DISABLE_ASM:

https://tahoe-lafs.org/buildbot-pycryptopp/builders/Kyle%20OpenBSD-amd64/builds/127/steps/bench/logs/stdio

Again, if you're concerned about this, look at the "Recent Uploads and
Downloads" page when you are uploading or downloading files. The AES
encryption usually takes something like 1/100 as long as the network
transfer does. So this performance penalty probably won't be
detectable to you.

Regards,

Zooko