From: "H. Peter Anvin" <hpa@zytor.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Christoph Lameter <cl@linux.com>,
Alok Kataria <akataria@vmware.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86: Reduce the default HZ value
Date: Thu, 07 May 2009 08:30:25 -0700 [thread overview]
Message-ID: <4A02FE91.8070006@zytor.com> (raw)
In-Reply-To: <20090507161440.5b9c067d@lxorguk.ukuu.org.uk>
Alan Cox wrote:
> On Thu, 7 May 2009 10:13:52 -0400 (EDT)
> Christoph Lameter <cl@linux.com> wrote:
>
>> I think we need to reduce the general tick frequency to be as low as
>> possible. With high resolution timers the tick frequency is just the
>> frequency with which the timer interrupt disturbs a running application.
>>
>> Are there any benefits remaining from frequent timer interrupts? I would
>> think that 60 HZ would be sufficient.
>
> 50 works for various european video apps, 60 breaks, 60 works for various
> US video apps, 50 breaks. Now that may have changed with all the select
> stuff being hrtimer based (which I'd missed).
Hence 300 Hz. ;)
> Hooray - finally someone admits the *real* problem here, and for power
> management too. Otherwise known as "referencing jiffies as a variable must
> die"
Amen. Also, "using HZ as a unit of measurement must die, too."
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2009-05-07 15:32 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-04 18:44 [PATCH] x86: Reduce the default HZ value Alok Kataria
2009-05-05 21:21 ` H. Peter Anvin
2009-05-05 21:44 ` Alan Cox
2009-05-05 22:09 ` Alok Kataria
2009-05-05 22:33 ` Alan Cox
2009-05-05 23:37 ` Alok Kataria
2009-05-07 14:09 ` Christoph Lameter
2009-05-07 15:12 ` Alan Cox
2009-05-05 21:57 ` Alok Kataria
2009-05-07 14:13 ` Christoph Lameter
2009-05-07 15:14 ` Alan Cox
2009-05-07 15:20 ` Christoph Lameter
2009-05-07 15:30 ` H. Peter Anvin [this message]
2009-05-07 15:40 ` Christoph Lameter
2009-05-07 16:55 ` Jeff Garzik
2009-05-07 17:09 ` Alan Cox
2009-05-07 17:55 ` Jeff Garzik
2009-05-07 19:51 ` Alan Cox
2009-05-07 20:03 ` Jeff Garzik
2009-05-07 20:30 ` Alan Cox
2009-05-07 16:37 ` Alok Kataria
2009-05-07 17:07 ` Peter Zijlstra
2009-05-07 17:13 ` Peter Zijlstra
2009-05-07 17:18 ` Peter Zijlstra
2009-05-07 17:20 ` Christoph Lameter
2009-05-07 17:39 ` Peter Zijlstra
2009-05-07 17:40 ` Christoph Lameter
2009-05-07 17:54 ` Paul E. McKenney
2009-05-07 17:51 ` Christoph Lameter
2009-05-07 19:51 ` Paul E. McKenney
2009-05-07 17:36 ` Paul E. McKenney
2009-05-07 17:38 ` Peter Zijlstra
2009-05-07 18:01 ` Paul E. McKenney
2009-05-07 18:12 ` Christoph Lameter
2009-05-07 19:06 ` Paul E. McKenney
2009-05-07 19:53 ` Alan Cox
2009-05-07 19:56 ` Christoph Lameter
2009-05-07 20:24 ` Alan Cox
2009-05-07 20:21 ` Christoph Lameter
2009-05-08 10:32 ` Peter Zijlstra
2009-05-08 12:50 ` Paul E. McKenney
2009-05-08 14:16 ` Christoph Lameter
2009-05-08 15:06 ` Paul E. McKenney
2009-05-07 17:18 ` Christoph Lameter
2009-05-07 17:37 ` Peter Zijlstra
2009-05-07 17:34 ` Christoph Lameter
2009-05-07 17:55 ` Peter Zijlstra
2009-05-07 17:55 ` Christoph Lameter
2009-05-07 17:19 ` Christoph Lameter
2009-05-07 17:45 ` Peter Zijlstra
2009-05-07 17:50 ` Christoph Lameter
2009-05-07 19:17 ` Peter Zijlstra
2009-05-07 19:38 ` Christoph Lameter
2009-05-07 21:01 ` H. Peter Anvin
2009-05-07 16:35 ` Chris Snook
2009-05-07 16:56 ` Alok Kataria
2009-05-07 20:29 ` Chris Snook
2009-05-07 20:34 ` Alan Cox
2009-05-07 22:16 ` Ravikiran G Thirumalai
2009-05-07 22:19 ` Alok Kataria
2009-05-08 9:31 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2009-05-12 19:45 devzero
2009-05-13 23:30 ` Alok Kataria
2009-05-14 20:25 devzero
2009-05-14 20:29 ` Alan Cox
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