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From: Arjan van de Ven <arjan@linux.intel.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Subject: Re: vmstat: use our own timer events
Date: Mon, 30 Apr 2007 07:12:08 -0700	[thread overview]
Message-ID: <4635F938.3060706@linux.intel.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0704292138480.1737@schroedinger.engr.sgi.com>

Christoph Lameter wrote:
> On Sun, 29 Apr 2007, Andrew Morton wrote:
> 
>>> on each node at the second and then each of the other processor on a
>>> node on a subsequent tick. That may be useful to keep a large amount
>>> of the second free of timer activity. Maybe the timer folks will have
>>> some feedback on this one?
>> The one-per-second timer interrupt will upset the people who are really
>> aggressive about power consumption (eg, OLPC).  Perhaps there isn't (yet)
>> an intersection between those people and SMP.
> 
> Well the cache_reaper of SLAB hits hard todays anyways. This will help
> if they switch to slub because the counter consolidation is much lighter 
> weight.

it's not about the weight. It's about waking up *at all*. I've been working
really hard to get a system with a reasonable average idle time (600ms+), but
I obviously had to patch the SLAB reaper to be at a different resolution...


> 
> I am fine with delaying this. I just wanted the timer guys to have a 
> chance to shape this a bit. Not sure what they want. What they did to the 
> cache_reaper in 2.6.20/21 is bad.

HUH? The cache_reaper DID NOT CHANGE with the round_jiffies() change.
Before it had a 3 jiffies per cpu offset, after it has a 3 jiffies per cpu offset.

  reply	other threads:[~2007-04-30 14:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-29  5:09 vmstat: use our own timer events Christoph Lameter
2007-04-29  8:15 ` Andrew Morton
2007-04-30  4:44   ` Christoph Lameter
2007-04-30 14:12     ` Arjan van de Ven [this message]
2007-04-30 17:42       ` Christoph Lameter
2007-05-02 18:13 ` Pallipadi, Venkatesh
2007-05-02 18:29   ` Christoph Lameter

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