Re: vmstat: use our own timer events

From: Arjan van de Ven
Date: Mon Apr 30 2007 - 10:13:37 EST


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.
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