From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Nish Aravamudan <nish.aravamudan@gmail.com>
Cc: Ray Lee <ray-lk@madrabbit.org>,
Roman Zippel <zippel@linux-m68k.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH/RFC] msleep() with hrtimers
Date: Tue, 17 Jul 2007 14:04:56 +1000 [thread overview]
Message-ID: <469C3FE8.30505@yahoo.com.au> (raw)
In-Reply-To: <29495f1d0707160908x32704c7o41ab7857ceac1558@mail.gmail.com>
Nish Aravamudan wrote:
> Well, before these changes, the only guarantee msleep() could make,
> just like the only guarantee schedule_timeout() could make, was that
> it would not return early. The 1-jiffy sleep was always tough to deal
> with, because of rounding and such. And it's simply exacerbated with
> HZ=100. It's not technically 20 times longer in all cases, it's 2
> jiffies longer, which depends on HZ, so varies from 2 msecs longer to
> 20 msecs longer.
I don't think you should rely on anything else actually, because Linux
is not an RT OS. If your driver needs a specific sequence in a given
amount of time, you have to do something like disable interrupts and
use delays.
--
SUSE Labs, Novell Inc.
next prev parent reply other threads:[~2007-07-18 16:29 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-15 22:42 [PATCH/RFC] msleep() with hrtimers Jonathan Corbet
2007-07-15 23:10 ` Arnd Bergmann
2007-07-16 10:48 ` Ingo Molnar
2007-07-16 11:39 ` Roman Zippel
2007-07-16 11:47 ` Ingo Molnar
2007-07-16 11:54 ` Roman Zippel
2007-07-16 11:57 ` Ingo Molnar
2007-07-16 12:05 ` Roman Zippel
2007-07-16 12:19 ` Ingo Molnar
2007-07-16 13:00 ` Roman Zippel
2007-07-16 14:09 ` Ingo Molnar
2007-07-16 14:32 ` Roman Zippel
2007-07-16 14:42 ` Jonathan Corbet
2007-07-16 15:18 ` Ingo Molnar
2007-07-16 15:43 ` Roman Zippel
2007-07-16 15:57 ` Ray Lee
2007-07-16 16:08 ` Nish Aravamudan
2007-07-17 4:04 ` Nick Piggin [this message]
2007-07-18 17:53 ` Nish Aravamudan
2007-07-16 16:10 ` Ingo Molnar
2007-07-16 16:55 ` Roman Zippel
2007-07-16 17:46 ` Jonathan Corbet
2007-07-20 12:49 ` Roman Zippel
2007-07-16 14:11 ` Roman Zippel
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