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Message-ID: <CAOLP8p4xKYuTaCVg1=OGiFFsnWVfMBidfO0jDZ1FfB1AcmU8Jg@mail.gmail.com>
Date: Thu, 2 Jan 2014 09:44:20 -0500
From: Bill Cox <waywardgeek@...il.com>
To: discussions@...sword-hashing.net
Subject: Re: Initial hashing function. Feedback welcome
I've done some hand optimization, and gotten the speed to be only about
2.2X slower than memmove when copying 2GB over itself. To get the speed, I
stopped reading randomly from the "from page", and read it linearly
instead. This seemed to help the optimizer quite a bit, and the output
still seems somewhat (but not perfectly) random according to dieharder
tests. This is my 3GHz Core i7 machine. keystretch on 2GB is taking .433
seconds while a memmove takes .2s.
Running multiple copies of memmove shows my system seems to handle about
23GB/s of memory bandwidth. Two copies of keystretch achieve about 13GB/s.
It's not maxing out memory bandwidth, but it's getting there...
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