From: Paul Mackerras <paulus@samba.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Neil Horman <nhorman@tuxdriver.com>,
Segher Boessenkool <segher@kernel.crashing.org>,
linux-kernel@vger.kernel.org, a.zummo@towertech.it,
jg@freedesktop.org
Subject: Re: [PATCH] RTC: Add mmap method to rtc character driver
Date: Wed, 26 Jul 2006 06:03:59 +1000 [thread overview]
Message-ID: <17606.31023.273943.551848@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <44C66C91.8090700@zytor.com>
H. Peter Anvin writes:
> Not really. This introduces a potentially very difficult support
> user-visible interface. Consider a tickless kernel -- you might end up
> taking tick interrupts ONLY to update this page, since you don't have
> any way of knowing when userspace wants to look at it.
It's not that bad; if userspace is running, the cpu isn't idle, so
there isn't the motivation to go tickless on that cpu. In other
words, if every cpu has suspended ticks, then no cpu can be running
stuff that needs to look at this page.
Paul.
next prev parent reply other threads:[~2006-07-25 20:07 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-25 17:41 Neil Horman
2006-07-25 17:55 ` Arjan van de Ven
2006-07-25 18:01 ` Jim Gettys
2006-07-25 18:22 ` Neil Horman
2006-07-25 18:32 ` Arjan van de Ven
2006-07-25 18:43 ` Neil Horman
2006-07-25 18:53 ` Arjan van de Ven
2006-07-25 19:03 ` Neil Horman
2006-07-25 19:06 ` Arjan van de Ven
2006-07-25 19:07 ` John W. Linville
2006-07-25 19:16 ` Arjan van de Ven
2006-07-25 19:08 ` H. Peter Anvin
2006-07-25 17:57 ` Segher Boessenkool
2006-07-25 18:28 ` Neil Horman
2006-07-25 18:56 ` Segher Boessenkool
2006-07-25 19:07 ` Neil Horman
2006-07-25 19:10 ` H. Peter Anvin
2006-07-25 19:21 ` Neil Horman
2006-07-25 19:31 ` Segher Boessenkool
2006-07-25 19:47 ` Neil Horman
2006-07-25 20:04 ` Dave Airlie
2006-07-25 20:24 ` H. Peter Anvin
2006-07-25 20:47 ` Neil Horman
2006-07-25 20:50 ` H. Peter Anvin
2006-07-25 22:25 ` Neil Horman
2006-07-25 22:33 ` H. Peter Anvin
2006-07-25 23:10 ` Neil Horman
2006-07-25 23:22 ` H. Peter Anvin
2006-07-26 0:03 ` Neil Horman
2006-07-25 23:29 ` David Lang
2006-07-26 0:18 ` Neil Horman
2006-07-25 23:29 ` Segher Boessenkool
2006-07-25 23:56 ` Neil Horman
2006-07-26 0:02 ` H. Peter Anvin
2006-07-26 0:20 ` Neil Horman
2006-07-26 0:36 ` H. Peter Anvin
2006-07-26 14:45 ` A better interface, perhaps: a timed signal flag Theodore Tso
2006-07-28 13:33 ` Steven Rostedt
2006-07-28 14:52 ` Theodore Tso
2006-07-28 15:05 ` Steven Rostedt
2006-07-28 16:41 ` Alan Cox
2006-07-28 16:44 ` Steven Rostedt
2006-07-28 20:01 ` Alan Cox
2006-07-28 20:12 ` Steven Rostedt
2006-07-28 20:36 ` Alan Cox
2006-07-28 20:31 ` Steven Rostedt
2006-07-28 17:11 ` H. Peter Anvin
2006-07-25 20:58 ` [PATCH] RTC: Add mmap method to rtc character driver Jim Gettys
2006-07-25 21:04 ` H. Peter Anvin
2006-07-25 21:14 ` Jim Gettys
2006-07-25 21:18 ` H. Peter Anvin
2006-07-25 21:39 ` Jim Gettys
2006-07-29 4:28 ` Bill Huey
2006-07-29 12:54 ` Neil Horman
2006-07-29 20:41 ` Bill Huey
2006-07-29 21:43 ` Neil Horman
2006-07-29 22:45 ` Keith Packard
2006-07-29 23:18 ` Edgar Toernig
2006-07-29 21:49 ` Edgar Toernig
2006-07-29 22:51 ` itimer again (Re: [PATCH] RTC: Add mmap method to rtc character driver) Bill Huey
2006-07-29 23:35 ` Nicholas Miell
2006-07-30 1:00 ` Bill Huey
2006-07-30 1:22 ` Nicholas Miell
2006-07-30 1:39 ` Bill Huey
2006-07-30 2:02 ` Nicholas Miell
2006-07-30 14:33 ` Theodore Tso
2006-07-30 22:20 ` Bill Huey
2006-07-31 15:40 ` Theodore Tso
2006-07-30 0:16 ` Edgar Toernig
2006-07-30 0:24 ` Bill Huey
2006-07-29 14:02 ` [PATCH] RTC: Add mmap method to rtc character driver Thomas Gleixner
2006-07-26 13:17 ` Martin J. Bligh
2006-08-02 3:54 ` john stultz
2006-08-02 4:26 ` H. Peter Anvin
2006-08-02 4:34 ` john stultz
2006-07-25 23:26 ` Segher Boessenkool
2006-07-26 0:10 ` Neil Horman
2006-07-25 20:03 ` Paul Mackerras [this message]
2006-07-25 23:27 ` Segher Boessenkool
2006-07-26 0:06 ` Neil Horman
2006-07-25 18:00 ` Jim Gettys
2006-07-25 18:17 ` Neil Horman
2006-07-26 15:16 ` Andi Kleen
2006-07-26 17:25 ` Jim Gettys
2006-07-27 23:53 ` Paul Mackerras
2006-07-28 3:29 ` Jim Gettys
2006-07-28 11:59 ` Neil Horman
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