From: Andries.Brouwer@cwi.nl
Date: Fri, 5 Sep 2003 11:16:05 +0200 (MEST)
Message-Id: <UTC200309050916.h859G5813732.aeb@smtp.cwi.nl>
To: Andries.Brouwer@cwi.nl, mpm@selenic.com
Subject: Re: [PATCH] add_mouse_randomness
Cc: linux-kernel@vger.kernel.org
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1179
Lines: 26

    From oxymoron@waste.org  Fri Sep  5 07:01:30 2003
    From: Matt Mackall <mpm@selenic.com>

    > Today:
    > Every keypress and every key release causes two calls of
    > add_mouse_randomness and one call of add_keyboard_randomness.
    > Key repeat causes lots of calls of add_mouse_randomness.
    > 
    > The random driver contains a mechanism (delta, delta2, delta3)
    > for estimating the amount of entropy in a stream of moments in
    > time. But the fact that every event causes two calls, very
    > quickly after each other, poisons this mechanism, and makes us
    > overestimate.

    The real problem is that the deltas are calculated from gigahertz
    cycle counters, but yes, we're calling too frequently and blowing away
    useful history. I've experimented with making the deltas per-source as
    well.

I wouldnt know what is wrong with using gigahertz cycle counters.
The deltas are already per-source.
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