Re: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree

From: Mark Lord
Date: Fri Nov 30 2007 - 22:44:49 EST


Arjan van de Ven wrote:
On Fri, 30 Nov 2007 22:31:17 -0500
Mark Lord <lkml@xxxxxx> wrote:

Arjan van de Ven wrote:
On Fri, 30 Nov 2007 22:14:08 -0500
Mark Lord <lkml@xxxxxx> wrote:

in -mm there is.. the QoS stuff allows you to set maximum
tolerable
..

That's encouraging, I think, but not for 2.6.24.

latency. If your app cant take any latency, you should set
those... and the side effect is that the kernel will not do
long-latency C-states or P-state transitions..
..

I don't mind the cpufreq changing (actually, I want it to drop in
cpugfreq to save power and keep the fan off), but the C-states just
kill this app.

The app is VMware. I force the max_state=1 when launching,
ah but then its' even easier... and can be done in 2.6.24 already.
VMWare after all has a kernel module, and the latency stuff is in
2.6.23 and 2.6.24 available inside the kernel already.
..

Oh, I'm perfectly happy to write my own kernel module if that's what

all you need to do in your kernel module is call

add_latency_constraint("mark_wants_his_mouse", 5);

Okay, and how to change it back again? (thanks)

Then why not have a sysfs entry for scripts to write to
to trigger the exact same end result? :)

Speaking of which.. what's with powertop on 2.6.24 ???
It's gone from 100-200 wakeups/sec to 20000 wakeups/sec !!!!!!!

ho hum.. Lenovo T61?
I have some reports that that happens once in a while (but it's not
limited to .24 and it's also real, it's not a powertop bug but it
actually is waking up that much)..
..

No, it's my hefty Dell Inspiron 9400.

And I just figured out the powertop: it needed the kernel timers
patch from the powertop site that was originally for 2.6.21..

Any chance of somebody actually pushing that patch upstream some year ??
Patch reproduced here for interest's sake only.
Hey, look who's on the Signed-off list for it, *Arjan* !

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