From: john stultz <johnstul@us.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Roman Zippel <zippel@linux-m68k.org>,
lkml <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] exponential update_wall_time
Date: Wed, 27 Sep 2006 16:20:21 -0700 [thread overview]
Message-ID: <1159399221.7297.16.camel@localhost> (raw)
In-Reply-To: <20060927150501.3d40e11e.akpm@osdl.org>
On Wed, 2006-09-27 at 15:05 -0700, Andrew Morton wrote:
> On Wed, 27 Sep 2006 12:35:33 -0700
> john stultz <johnstul@us.ibm.com> wrote:
>
> > + while (offset > clock->cycle_interval << (shift + 1))
> > + shift++;
>
> hurts my brain.
Yea. Its not the most obvious patch, but the complexity is pretty
isolated.
> I have a vague feeling that this can be done with
> something like ffz(~(offset/clock->cycle_interval))+epsilon, but that hurts
> my brain too.
Agreed. I don't want to obfuscate this code much more. In my opinion,
the loop is tightly bounded and not expensive enough to try to optimize.
thanks
-john
next prev parent reply other threads:[~2006-09-27 23:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-27 19:35 [RFC] exponential update_wall_time john stultz
2006-09-27 20:08 ` Ingo Molnar
2006-09-27 20:24 ` Thomas Gleixner
2006-09-27 22:05 ` Andrew Morton
2006-09-27 23:20 ` john stultz [this message]
2006-09-27 23:04 ` Roman Zippel
2006-09-27 23:13 ` john stultz
2006-09-27 23:40 ` Roman Zippel
2006-09-28 0:28 ` john stultz
2006-09-28 21:01 ` Roman Zippel
2006-09-28 21:11 ` Ingo Molnar
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