From: Miroslav Lichvar <mlichvar@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: John Stultz <johnstul@us.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [GIT pull] ntp updates for 2.6.31
Date: Tue, 23 Jun 2009 21:49:16 +0200 [thread overview]
Message-ID: <20090623194916.GA18657@localhost> (raw)
In-Reply-To: <20090623191838.GB14852@elte.hu>
On Tue, Jun 23, 2009 at 09:18:38PM +0200, Ingo Molnar wrote:
>
> * Miroslav Lichvar <mlichvar@redhat.com> wrote:
>
> > > > I'm not very familiar with the PPS API, is there something
> > > > wrong with it?
> > >
> > > The PPS patches i've seen just export IRQ timestamps to
> > > user-space.
> > >
> > > That is not very robust in my opinion when it comes to do time
> > > approximations - to get quick, low-latency action and precise
> > > measurements it's best to keep the critical path as short as
> > > possible, and within a single source code repository: i.e.
> > > within the kernel.
> >
> > That's what kernel PPS discipline does, it will be probably
> > included later. Its performance is an order or two better than the
> > PLL/FLL discipline.
>
> Is there some kernel patch i can look at?
It's in the old PPSkit patches for 2.4 kernels, function hardpps().
--
Miroslav Lichvar
next prev parent reply other threads:[~2009-06-23 19:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-15 14:06 [GIT pull] ntp updates for 2.6.31 Thomas Gleixner
2009-06-15 20:16 ` john stultz
2009-06-15 23:41 ` john stultz
2009-06-16 9:06 ` Ingo Molnar
2009-06-16 11:29 ` Thomas Gleixner
2009-06-16 12:52 ` Miroslav Lichvar
2009-06-17 15:38 ` John Stultz
2009-06-17 16:51 ` Ingo Molnar
2009-06-17 17:23 ` Miroslav Lichvar
2009-06-17 17:26 ` Ingo Molnar
2009-06-17 17:55 ` John Stultz
2009-06-18 12:13 ` Miroslav Lichvar
2009-06-23 9:57 ` Ingo Molnar
2009-06-23 13:16 ` Miroslav Lichvar
2009-06-23 13:36 ` Ingo Molnar
2009-06-23 14:33 ` Miroslav Lichvar
2009-06-23 19:18 ` Ingo Molnar
2009-06-23 19:49 ` Miroslav Lichvar [this message]
2009-06-23 21:41 ` john stultz
2009-06-24 9:29 ` Alan Cox
2009-06-24 13:39 ` Martin Schwidefsky
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