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Date: Sun, 14 Mar 2010 19:57:38 +0100
From: "Magnum, P.I." <>
Subject: Re: problem with initializing mpirun extended

Solar Designer wrote:
>> If you start a job in background, the check the logs, it may 
>> very well stop after the "748892 preprocessed word mangling rules" line 
>> you mention for a very long time. But if you issue a kill -HUP to that 
>> process, it will flush its log buffer and you'll see it is in fact working.
> I think the same would be happening with a single process.

Maybe it's just more noticable. Using a single process, you can just hit 
a key and get updated statistics. When running an MPI job you need to 
look at the logfile, or run john --status, but neither will tell you 
correct info unless file buffers are flushed first. If your job is 
spread over remote hosts too, it starts to get tedious (so of course you 
script it).

> There was a relevant change between 1.7.4 and - LOG_BUFFER_SIZE
> was increased from 4 KB to 32 KB.  Maybe this confused you into thinking
> that MPI had something to do with the change in behavior you've observed.

That makes sense. No wonder I couldn't find it in the mpi10 diff :)

> Rather than reduce LOG_BUFFER_SIZE, which may hurt performance with a
> lot of passwords getting cracked quickly or with a lot of rules and a
> small wordlist, you may lower the "Save" setting in john.conf - say,
> going from 600 down to 60 seconds won't affect performance significantly.

Great, I never thought of that. This will do wonders for some debugging 
too, using Save = 1


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