From: Johannes Weiner <hannes@cmpxchg.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
john stultz <johnstul@us.ibm.com>,
Richard Henderson <rth@twiddle.net>,
lkml <linux-kernel@vger.kernel.org>,
Matt Turner <mattst88@gmail.com>
Subject: Re: [RFC][PATCH] Convert alpha to use clocksource
Date: Mon, 22 Mar 2010 17:41:37 +0100 [thread overview]
Message-ID: <20100322164137.GA12625@cmpxchg.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1003221521440.3147@localhost.localdomain>
On Mon, Mar 22, 2010 at 03:22:12PM +0100, Thomas Gleixner wrote:
> On Mon, 22 Mar 2010, Johannes Weiner wrote:
> > > Though, even after a glance over the clocksource code, I've not
> > > gotten yet to how one could estimate the "shift" value...
> > > Any hints?
> >
> > I had the same problem with xtensa and added a comment about what I
> > did in there, maybe it helps:
> >
> > arch/xtensa/kernel/time.c
> >
> > I took the upper bound of the multiplicator (nsecs per counter unit)
> > and subtracted its logarithm from my available 32 bits. The result
> > is the highest possible shift value that works for the clocksource.
>
> clocks_calc_mult_shift() is what you are looking for.
Oh, thanks! That was not yet around at the time.
Hannes
prev parent reply other threads:[~2010-03-22 16:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-18 2:01 [RFC][PATCH] Convert alpha to use clocksource John Stultz
2010-03-18 14:32 ` Richard Henderson
2010-03-18 17:55 ` john stultz
2010-03-18 21:40 ` Ivan Kokshaysky
2010-03-18 22:19 ` john stultz
2010-03-19 10:07 ` Ivan Kokshaysky
2010-03-19 16:47 ` Matt Turner
2010-03-19 17:13 ` Richard Henderson
2010-03-22 11:17 ` Johannes Weiner
2010-03-22 14:22 ` Thomas Gleixner
2010-03-22 16:41 ` Johannes Weiner [this message]
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