From: "Jörn Engel" <joern@logfs.org>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Stephan Mueller <smueller@chronox.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Developers List <linux-kernel@vger.kernel.org>,
macro@linux-mips.org, ralf@linux-mips.org, dave.taht@gmail.com,
blogic@openwrt.org, andrewmcgr@gmail.com, geert@linux-m68k.org,
tg@mirbsd.de
Subject: Re: [PATCH,RFC] random: collect cpu randomness
Date: Sun, 2 Feb 2014 22:35:48 -0500 [thread overview]
Message-ID: <20140203033548.GC9499@logfs.org> (raw)
In-Reply-To: <20140203013922.GB6264@thunk.org>
On Sun, 2 February 2014 20:39:22 -0500, Theodore Ts'o wrote:
>
> The real question is how much overhead does it add, and is it worth
> it. Jörn, I take it that was the reason for creating an even faster,
> but weaker mixing function? Was the existing "fast mix" causing a
> measurable overhead, or was this your just being really paranoid about
> not adding anything to the various kernel fastpaths?
It was paranoia. And I am still somewhat paranoid and don't trust my
benchmark results yet. Maybe on an 1024-CPU Altix with a 100k-thread
workload the overhead is too much. Just because I couldn't measure a
difference on my wimpy notebook does not mean much.
Jörn
--
One of the painful things about our time is that those who feel certainty
are stupid, and those with any imagination and understanding are filled
with doubt and indecision.
-- Bertrand Russell
next prev parent reply other threads:[~2014-02-03 3:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-02 20:36 [PATCH,RFC] random: collect cpu randomness Jörn Engel
2014-02-02 21:25 ` Stephan Mueller
2014-02-03 1:24 ` Jörn Engel
2014-02-03 1:28 ` H. Peter Anvin
2014-02-03 13:36 ` Stephan Mueller
2014-02-03 1:39 ` Theodore Ts'o
2014-02-03 3:35 ` Jörn Engel [this message]
2014-02-03 12:54 ` Thorsten Glaser
2014-02-03 13:06 ` Stephan Mueller
2014-02-03 15:50 ` Jörn Engel
2014-02-03 16:37 ` Theodore Ts'o
2014-02-03 18:48 ` Jörn Engel
2014-03-23 18:00 ` [PATCH] random: mix all saved registers into entropy pool Jörn Engel
2014-02-03 21:54 ` [PATCH,RFC] random: collect cpu randomness Maciej W. Rozycki
2014-02-03 22:44 ` Theodore Ts'o
2014-02-06 22:20 ` Kees Cook
2014-02-06 22:21 ` Dave Taht
2014-02-07 7:44 ` Jörn Engel
2014-02-20 9:50 ` Paolo Bonzini
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