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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130923150222.GA13764@logfs.org \
--to=joern@logfs.org \
--cc=dave.taht@bufferbloat.net \
--cc=fweisbec@gmail.com \
--cc=john.stultz@linaro.org \
--cc=jvpeetz@web.de \
--cc=linux-kernel@vger.kernel.org \
--cc=smueller@chronox.de \
--cc=tglx@linutronix.de \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.