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From: "Theodore Ts'o" <tytso@mit.edu>
To: John Stultz <john.stultz@linaro.org>
Cc: Stephan Mueller <smueller@chronox.de>,
	LKML <linux-kernel@vger.kernel.org>,
	dave.taht@bufferbloat.net
Subject: Re: [PATCH] /dev/random: Insufficient of entropy on many architectures
Date: Tue, 10 Sep 2013 16:38:53 -0400	[thread overview]
Message-ID: <20130910203853.GG29237@thunk.org> (raw)
In-Reply-To: <CANcMJZAHuXNQ4eUx+qpVnfJTg625HkJU_9pgBP24ykkmBww3yw@mail.gmail.com>

On Tue, Sep 10, 2013 at 12:38:56PM -0700, John Stultz wrote:
> So the end of timekeeping_init() may not be what you want here. This
> only means we've started up the timekeping core with only the default
> clocksource (with only few exceptions, this is almost always jiffies).
> Then as clocksource drivers are initialized, they are registered and
> the timekeeping core will switch over to the best available
> clocksource.  Also, to avoid the churn at boot of switching to every
> clocksource registered, we queue them up and wait until fs_init time
> to switch to whatever is the best available then.

Is there any indication in the clocksource structures where we can
determine what the cost (in CPU, time, bus overhead, etc.) for a
particular clock source, verus the granularity of the clock source?

Also, is it always safe to read from a clock source from an interrupt
handler?

Thanks,

					- Ted

  parent reply	other threads:[~2013-09-10 20:38 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-10 11:31 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 [this message]
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
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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