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Date: Tue, 19 Jun 2012 17:31:39 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: [patch] optional new raw sha1 implemetation

On Tue, Jun 19, 2012 at 03:11:30PM +0200, Tavis Ormandy wrote:
> I don't think so, the performance impact is indeed very small, 0.1%
> sounds right. Still, I want that 0.1% :-)

Understood.

0.1% was almost a worst case estimate.  How large is your actual
max_keys_per_crypt?  Is your cmp_one() really as heavy as one SHA-1
computation?  Are you frequently running this against exactly 1 or 2
loaded hashes (not 3 or more)?

I am not sure if there's a way to reclaim that 0.1% without incurring it
(or more) elsewhere.  For example, you can do full instead of partial
hash comparisons in cmp_all(), but this might make its code slower
(through differences in the code and maybe through worse locality of
reference when full rather than partial binary hashes are in memory).

Alexander

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