From: "Jörn Engel" <joern@logfs.org>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Jörg-Volker Peetz" <jvpeetz@web.de>,
"John Stultz" <john.stultz@linaro.org>,
"Stephan Mueller" <smueller@chronox.de>,
LKML <linux-kernel@vger.kernel.org>,
dave.taht@bufferbloat.net,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>
Subject: Re: [PATCH,RFC] random: make fast_mix() honor its name
Date: Mon, 23 Sep 2013 11:02:22 -0400 [thread overview]
Message-ID: <20130923150222.GA13764@logfs.org> (raw)
In-Reply-To: <20130923024338.GF7321@thunk.org>
On Sun, 22 September 2013 22:43:38 -0400, Theodore Ts'o wrote:
> On Sun, Sep 22, 2013 at 08:16:23PM -0400, Jörn Engel wrote:
> > How about we switch between the two mixing functions depending on the
> > interrupt load? If this CPU has seen fewer than 1000 interrupts in
> > the last second, use the better one, otherwise us the cheaper one?
>
> I guess the question here is whether it's worth it. On a 2.8 GHz
> laptop Ivy Bridge chip the numbers are:
Then let us assume for now it is not worth it. When I finally get
around to generating profiles for my insane system we can revisit the
issue.
> I am very strongly of the opinion that the number of systems where you
> have an embedded system with that kind of inane interrupt rate is the
> 0.00000000001% case.
That would be one machine in 10^13? I doubt we have reached 10^13
machines running Linux in all of history, so a single example would
defeat your very strong opinion. ;)
Anyway, let me collect some real numbers before we argue any further.
And thank you for your maintainership. It may not appear that way,
but I have _very_ little to complain about in drivers/char/random.c.
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:[~2013-09-23 16:20 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-10 11:31 [PATCH] /dev/random: Insufficient of entropy on many architectures Stephan Mueller
2013-09-10 11:46 ` Geert Uytterhoeven
2013-09-10 15:04 ` Theodore Ts'o
2013-09-10 16:54 ` Stephan Mueller
2013-09-10 18:25 ` Theodore Ts'o
2013-09-10 19:15 ` Stephan Mueller
2013-10-10 6:50 ` Pavel Machek
2013-10-14 21:13 ` Theodore Ts'o
2013-09-10 20:48 ` Geert Uytterhoeven
2013-09-10 21:14 ` Theodore Ts'o
2013-09-11 6:49 ` Stephan Mueller
2013-09-12 11:59 ` Geert Uytterhoeven
2013-09-12 12:08 ` Stephan Mueller
2013-09-12 12:15 ` Geert Uytterhoeven
2013-09-12 12:35 ` Stephan Mueller
2013-09-12 12:47 ` Geert Uytterhoeven
2013-09-12 12:57 ` Stephan Mueller
2013-09-12 21:18 ` Jörn Engel
2013-09-13 11:33 ` Thorsten Glaser
2013-09-12 14:25 ` Theodore Ts'o
2013-09-10 19:38 ` John Stultz
2013-09-10 19:44 ` John Stultz
2013-09-10 19:47 ` Stephan Mueller
2013-09-10 20:35 ` John Stultz
2013-09-10 20:38 ` Theodore Ts'o
2013-09-10 20:46 ` John Stultz
2013-09-10 21:10 ` Theodore Ts'o
2013-09-10 22:08 ` John Stultz
2013-09-10 22:33 ` Theodore Ts'o
2013-09-11 0:31 ` John Stultz
2013-09-11 0:50 ` Theodore Ts'o
2013-09-11 1:14 ` John Stultz
2013-09-12 20:46 ` H. Peter Anvin
2013-09-12 21:07 ` Jörn Engel
2013-09-12 23:31 ` Theodore Ts'o
2013-09-12 23:35 ` Jörn Engel
2013-09-13 0:00 ` Jörn Engel
2013-09-16 15:40 ` [PATCH,RFC] random: make fast_mix() honor its name Jörn Engel
2013-09-21 21:25 ` Theodore Ts'o
2013-09-21 21:41 ` Theodore Ts'o
2013-09-22 3:05 ` Theodore Ts'o
2013-09-22 21:01 ` Jörg-Volker Peetz
2013-09-22 21:27 ` Theodore Ts'o
2013-09-22 20:53 ` Jörn Engel
2013-09-22 23:36 ` Theodore Ts'o
2013-09-23 0:16 ` Jörn Engel
2013-09-23 2:43 ` Theodore Ts'o
2013-09-23 15:02 ` Jörn Engel [this message]
2013-09-23 7:39 ` Jörg-Volker Peetz
2013-09-22 20:31 ` Jörn Engel
2013-09-22 20:14 ` Jörn Engel
2013-09-12 21:31 ` [PATCH] /dev/random: Insufficient of entropy on many architectures Jörn Engel
2013-09-13 5:36 ` Stephan Mueller
2013-09-13 11:54 ` Thorsten Glaser
2013-09-13 19:29 ` Theodore Ts'o
2013-09-13 15:26 ` Jörn Engel
2013-09-13 18:59 ` Theodore Ts'o
2013-09-15 11:12 ` Stephan Mueller
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