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From: Pavel Machek <pavel@ucw.cz>
To: Stephan Mueller <smueller@chronox.de>
Cc: Theodore Ts'o <tytso@mit.edu>,
	Sandy Harris <sandyinchina@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-crypto@vger.kernel.org, Jason Cooper <jason@lakedaemon.net>,
	John Denker <jsd@av8n.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <andi@firstfloor.org>
Subject: Re: random(4) changes
Date: Tue, 26 Apr 2016 21:41:55 +0200	[thread overview]
Message-ID: <20160426194155.GB11111@amd> (raw)
In-Reply-To: <1948798.MKebf3xYm7@positron.chronox.de>

Hi!

> > > > When dropping the add_disk_randomness function in the legacy
> > > > /dev/random, I
> > > > would assume that without changes to add_input_randomness and
> > > > add_interrupt_randomness, we become even more entropy-starved.
> > > 
> > > Sure, but your system isn't doing anything magical here.  The main
> > > difference is that you assume you can get almost a full bit of entropy
> > > out of each interrupt timing, where I'm much more conservative and
> > > assume we can only get 1/64th of a bit out of each interrupt timing.
> > 
> > Maybe 1/64th of a bit is a bit too conservative? I guess we really
> > have more than one bit of entropy on any system with timestamp
> > counter....
> > 
> > Making it 1/2 of bit (or something) should be very easy way to improve
> > entropy early during boot...
> 
> I can easily settle on 1/2 bit here. The LRNG currently uses 0.9 bits which 
> are based on measurements plus a safety margin. But I see no issue to even 
> lower it further to, say, 1/2.

No, you don't need to change anything. But maybe mainline rng should
change.

									Pavel
									
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  reply	other threads:[~2016-04-26 19:41 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-22 22:27 random(4) changes Sandy Harris
2016-04-23  7:52 ` Stephan Mueller
2016-04-24  2:03 ` Theodore Ts'o
2016-04-24  8:03   ` Stephan Mueller
2016-04-26  3:07     ` Theodore Ts'o
2016-04-26 11:04       ` Herbert Xu
2016-04-26 20:47         ` Andi Kleen
2016-04-27  4:23           ` Herbert Xu
2016-04-26 18:24       ` Stephan Mueller
2016-04-26 18:44       ` Pavel Machek
2016-04-26 18:55         ` Stephan Mueller
2016-04-26 19:41           ` Pavel Machek [this message]
2016-04-25 16:06 ` Andi Kleen
2016-04-25 17:25   ` Stephan Mueller
2016-04-25 17:38     ` Andi Kleen
2016-04-25 17:56       ` Stephan Mueller
2016-04-25 19:35         ` Andi Kleen
2016-04-26 12:01           ` Stephan Mueller
2016-04-27 17:47           ` Stephan Mueller
2016-04-26  1:00   ` Theodore Ts'o
2016-04-26 12:42   ` Sandy Harris
2016-04-26  1:59 George Spelvin
2016-04-26 18:43 ` Stephan Mueller
2016-04-26 20:43   ` George Spelvin
2016-04-26 21:01     ` Stephan Mueller
2016-04-27  0:23       ` George Spelvin
2016-04-27 18:03         ` George Spelvin
2016-04-28 20:15         ` Stephan Mueller
2016-04-29  7:29           ` George Spelvin
2016-04-29  8:02             ` Stephan Mueller
2016-04-29  9:34               ` George Spelvin
2016-04-29  9:53                 ` Stephan Mueller
2016-04-29 11:04                   ` George Spelvin
2016-04-29 11:18                     ` Stephan Mueller
2016-04-29 18:02                       ` George Spelvin
2016-04-29 18:41                         ` Stephan Mueller
2016-04-29 20:08                           ` George Spelvin
2016-04-29 21:54                             ` Stephan Mueller
2016-04-29 22:32                               ` George Spelvin
2016-04-29  0:47         ` George Spelvin

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