From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: chpoph <chpoph@gmail.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Viresh Kumar <viresh.kumar@linaro.org>,
Nicolas Pitre <nico@linaro.org>,
Liviu Dudau <Liviu.Dudau@arm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
will.deacon@arm.com
Subject: Re: udelay function delays the wrong time interval in multiprocessor system, if ARCH_HAS_READ_CURRENT_TIMER is not defined and on current timer is used.
Date: Fri, 15 Mar 2013 18:14:49 +0000 [thread overview]
Message-ID: <20130315181449.GX4977@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <CAM16m2=6S11d+eSSwQJ2f=nO6dM4K-dGKf3TR-z0nyBUyw=YxQ@mail.gmail.com>
On Sat, Mar 16, 2013 at 12:08:54AM +0800, chpoph wrote:
> If ARCH_HAS_READ_CURRENT_TIMER is not defined and on current timer is
> used for udelay, then __loop_delay and __loop_const_udelay is used to
> delay a specific time interval. but in delay-loop.S, loops_per_jiffy
> (not per cpu data) is used to calculate the number of loops. in SMP
> system, udelay delays the wrong time interval if two cpus running at
> different frequency.
We don't support different CPUs running at different frequencies with
the delay loop. Sorry.
next prev parent reply other threads:[~2013-03-15 18:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-15 16:08 chpoph
2013-03-15 18:14 ` Russell King - ARM Linux [this message]
2013-03-16 3:32 ` chpoph
2013-03-17 20:05 ` Will Deacon
2013-03-17 23:08 ` Russell King - ARM Linux
2013-03-18 14:40 ` chpoph
2013-03-18 15:25 ` Russell King - ARM Linux
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=20130315181449.GX4977@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=Liviu.Dudau@arm.com \
--cc=chpoph@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nico@linaro.org \
--cc=stable@vger.kernel.org \
--cc=viresh.kumar@linaro.org \
--cc=will.deacon@arm.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®