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Message-ID: <4D644BB1.4050302@bredband.net>
Date: Wed, 23 Feb 2011 00:50:09 +0100
From: magnum <rawsmooth@...dband.net>
To: john-users@...ts.openwall.com
Subject: Incremental mode progress and ETA

As a spinoff of recent experiments with better MPI splitting, I ended up 
writing a progress (percentage) and ETA patch for Incremental mode.

It is dead simple and works just fine but I'd like to improve it if 
possible. It calculates the total number of possible candidates from 
real_count and this seem to end up with a valid figure in all 
situations. So how many have we tried? The current solution is just a 
64-bit counter that increments for every candidate produced.

Now to the actual question: Is there by any chance some kind of 
reasonably light formula that could be used to calculate this number 
instead, from the various parameters and variables already used in the 
process? Or is that question the reason we don't already have this 
feature? I've tried to get a grip of how Incremental works but it beats me.

Unless there is such a formula, with all cool patches pouring in now I 
think I'll release it as-is, not just for MPI but as a separate patch. 
We could have a Makefile feature for disabling it in case it ends up 
hitting performance in some environments. On my gear it doesn't seem to 
have any measurable impact on performance even with the very fastest 
hashes, in fact it sometimes ends up faster.

However there is another advantage with calculating it from already used 
data: we could finally get to know how far that low-prio job we've been 
running for ages have progressed (my current patch disables progress 
output unless the counter was saved in an extra line in the .rec file). 
Come to think of it, if there is an easy-but-pretty-slow way of 
calculating it, I could keep the counter and only use the formula when 
restoring an old job that lacks the counter.

kudos & regards,
magnum

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