All of lore.kernel.org
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Iram Shahzad <iram.shahzad@jp.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: hrtimer: about hres_active
Date: Tue, 11 May 2010 10:33:35 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LFD.2.00.1005111032200.3401@localhost.localdomain> (raw)
In-Reply-To: <D1C79E74038141C1BCD3EF70A5032E34@rainbow>

Iram,

please do _NOT_ top post.

On Tue, 11 May 2010, Iram Shahzad wrote:
> > No. The system switches to high resolution mode late in the boot
> > process and it does so only when there is high res capable hardware
> > available.
> 
> So far as I checked, hres_active is set to 1 in hrtimer_switch_to_hres.
> hrtimer_switch_to_hres is only called from hrtimer_run_pending.
> And hrtimer_run_pending is called from timer wheel softirq.
> That is why I concluded that hres_active is set at 1st timer softirq.
> Do you just mean that it is not the 1st softirq, or do you
> mean that in some other place in the late boot process
> there is another code which sets hres_active?

It happens from softirq context, but not from the 1st softirq.
 
> And is it correct that hres_active remains 1 forever once set to it?

Yes. There is no way back.
 
Thanks,

	tglx

      reply	other threads:[~2010-05-11  8:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-06  6:03 [PATCH 0/2] ftrace: updates for powerpc Steven Rostedt
2009-02-06  6:03 ` [PATCH 1/2] ftrace, powerpc: replace debug macro with proper pr_deug Steven Rostedt
2009-02-06  6:07   ` Steven Rostedt
2009-02-06  6:07     ` Steven Rostedt
2009-02-06  7:05   ` Benjamin Herrenschmidt
2009-02-06 13:29     ` Steven Rostedt
2009-02-06  6:03 ` [PATCH 2/2] powerpc, ftrace: fix compile error when modules not configured Steven Rostedt
2009-02-06  6:07   ` Steven Rostedt
2009-02-06  6:07     ` Steven Rostedt
2009-02-06  6:23   ` Michael Neuling
2009-02-06  6:23     ` Michael Neuling
2009-02-06  6:27     ` Steven Rostedt
2009-02-06  7:04 ` [PATCH 0/2] ftrace: updates for powerpc Benjamin Herrenschmidt
2009-02-06 13:28   ` Steven Rostedt
2010-05-10 10:27 ` hrtimer: about hres_active Iram Shahzad
2010-05-10 15:12   ` Thomas Gleixner
2010-05-11  1:39     ` Iram Shahzad
2010-05-11  8:33       ` Thomas Gleixner [this message]

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=alpine.LFD.2.00.1005111032200.3401@localhost.localdomain \
    --to=tglx@linutronix.de \
    --cc=iram.shahzad@jp.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    /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.