[tahoe-dev] disabling optimized assembly in pycryptopp
Zooko O'Whielacronx
zookog at gmail.com
Fri Apr 12 08:59:34 UTC 2013
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
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