From: Thomas Gleixner <tglx@linutronix.de>
To: Daniel Walker <dwalker@mvista.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, johnstul@us.ibm.com, mingo@elte.hu
Subject: Re: [PATCH] timekeeping: drop irq-context clocksource polling
Date: Sun, 08 Apr 2007 10:33:19 +0200 [thread overview]
Message-ID: <1176021199.28263.529.camel@localhost.localdomain> (raw)
In-Reply-To: <1175981431.15973.158.camel@imap.mvista.com>
On Sat, 2007-04-07 at 14:30 -0700, Daniel Walker wrote:
> On Sat, 2007-04-07 at 22:50 +0200, Thomas Gleixner wrote:
> > On Sat, 2007-04-07 at 10:43 -0700, Daniel Walker wrote:
> > > Looks like this path ,
> > >
> > > arch/i386/kernel/tsc.c: time_cpufreq_notifier(); <-- takes xtime_lock
> > > mark_tsc_unstable();
> > > clocksource_change_rating(&clocksource_tsc, 0);
> > > timekeeping_change_clocksource(); <-- takes xtime_lock
> > >
> > >
> > > I'm not sure why the time_cpufreq_notifier is taking the xtime_lock tho .
> >
> > Simply because it fiddles with variables which are relevant for
> > timekeeping.
>
> loops_per_jiffy perhaps?
Oh well, this is a leftover from the days where we tried to use TSC
despite of frequency changes. It still modifies the scale factor of the
tsc clocksource.
I agree that it can be removed as we switch off TSC anyway in that case.
tglx
next prev parent reply other threads:[~2007-04-08 8:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-05 21:03 [PATCH] timekeeping: drop irq-context clocksource polling Daniel Walker
2007-04-05 21:25 ` john stultz
2007-04-05 21:29 ` Daniel Walker
2007-04-05 21:38 ` john stultz
2007-04-05 21:36 ` Andrew Morton
2007-04-05 21:50 ` john stultz
2007-04-07 1:21 ` Andrew Morton
2007-04-07 2:04 ` Daniel Walker
2007-04-07 10:19 ` Andrew Morton
2007-04-07 17:43 ` Daniel Walker
2007-04-07 20:50 ` Thomas Gleixner
2007-04-07 21:30 ` Daniel Walker
2007-04-08 8:33 ` Thomas Gleixner [this message]
2007-04-08 20:02 ` Daniel Walker
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