From: Andrew Morton <akpm@linux-foundation.org>
To: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: "Mark Lord" <lkml@rtr.ca>,
"Arjan van de Ven" <arjan@infradead.org>, <abelay@novell.com>,
<lenb@kernel.org>, "Ingo Molnar" <mingo@elte.hu>,
<linux-kernel@vger.kernel.org>, <linux-acpi@vger.kernel.org>
Subject: Re: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree
Date: Wed, 2 Jan 2008 16:51:57 -0800 [thread overview]
Message-ID: <20080102165157.2150f2d2.akpm@linux-foundation.org> (raw)
In-Reply-To: <924EFEDD5F540B4284297C4DC59F3DEE4FC485@orsmsx423.amr.corp.intel.com>
On Wed, 2 Jan 2008 16:06:20 -0800 "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> wrote:
>
>
> >-----Original Message-----
> >From: Mark Lord [mailto:lkml@rtr.ca]
> >Sent: Wednesday, January 02, 2008 3:42 PM
> >To: Arjan van de Ven
> >Cc: Pallipadi, Venkatesh; Andrew Morton; abelay@novell.com;
> >lenb@kernel.org; Ingo Molnar; linux-kernel@vger.kernel.org;
> >linux-acpi@vger.kernel.org
> >Subject: Re: + restore-missing-sysfs-max_cstate-attr.patch
> >added to -mm tree
> >
> >Arjan van de Ven wrote:
> >> On Fri, 30 Nov 2007 22:31:17 -0500
> >> Mark Lord <lkml@rtr.ca> wrote:
> >>
> >>> Arjan van de Ven wrote:
> >>>> On Fri, 30 Nov 2007 22:14:08 -0500
> >>>> Mark Lord <lkml@rtr.ca> 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);
> >>
> >> or so
> >..
> >
> >Dredging up an old regression again now:
> >
> >The "make my own module to replace /sys/.../max_cstate" doesn't work
> >for the single-core machine we use a lot around here.
> >
> >VMware is totally sluggish unless I go to another text window
> >and do this:
> >
> > while ( true ); do echo -n ; done
> >
> >At which point VMware performs well again,
> >the same as with "echo 1 > max_cstate" in 2.6.23.
> >
> >Anyone got any suggestions on how to fix this regression
> >or work around it for 2.6.24 ?
> >
>
> Easiest and clean way to do it is to have a driver with
> set_acceptable_latency() for 1uS or so in init and
> remove_acceptable_latency() at exit.
err, you appear to be suggesting that Mark patch his kernel to make it work
as well as 2.6.23? That would be a wrong answer.
This regression was known six weeks ago. What do we need to do (or revert)
to fix it in 2.6.24?
next prev parent reply other threads:[~2008-01-03 0:57 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200711302153.lAULrZ7n026255@imap1.linux-foundation.org>
[not found] ` <924EFEDD5F540B4284297C4DC59F3DEE2FAE6A@orsmsx423.amr.corp.intel.com>
2007-11-30 22:20 ` + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree Andrew Morton
2007-11-30 22:37 ` Pallipadi, Venkatesh
2007-12-01 2:52 ` Mark Lord
2007-12-01 3:02 ` Arjan van de Ven
2007-12-01 3:14 ` Mark Lord
2007-12-01 3:18 ` Arjan van de Ven
2007-12-01 3:31 ` Mark Lord
2007-12-01 3:44 ` Mark Lord
2007-12-01 3:48 ` Mark Lord
2007-12-01 4:02 ` Mark Lord
2007-12-01 4:31 ` Mark Lord
2007-12-01 23:43 ` 20000+ wake-ups/second in 2.6.24. Bug? Mark Lord
2007-12-01 23:46 ` Arjan van de Ven
2007-12-01 23:55 ` Mark Lord
2007-12-02 0:13 ` Arjan van de Ven
2007-12-02 1:10 ` Andres Freund
2007-12-02 0:20 ` Rafael J. Wysocki
2008-02-04 17:29 ` Mark Lord
2008-02-04 17:50 ` Arjan van de Ven
2008-02-04 19:17 ` Mark Lord
2007-12-02 14:41 ` Adrian Bunk
2007-12-02 14:59 ` Mark Lord
2007-12-02 15:12 ` Adrian Bunk
2007-12-02 15:45 ` Mark Lord
2007-12-02 15:45 ` Mark Lord
2007-12-02 15:49 ` Mark Lord
2008-01-02 23:41 ` + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree Mark Lord
2008-01-03 0:06 ` Pallipadi, Venkatesh
2008-01-03 0:51 ` Andrew Morton [this message]
2008-01-03 1:12 ` Pallipadi, Venkatesh
2008-01-03 4:25 ` Mark Lord
2008-01-03 4:18 ` Mark Lord
2008-01-04 2:16 ` Venki Pallipadi
2008-01-04 3:16 ` Mark Lord
2008-01-04 21:52 ` Mark Lord
2008-01-04 21:59 ` Pallipadi, Venkatesh
2008-01-05 16:27 ` Mark Lord
2008-01-06 21:34 ` Mark Lord
2008-01-07 7:18 ` Andrew Morton
2008-01-07 14:07 ` Arjan van de Ven
2008-01-07 15:07 ` Mark Lord
2008-01-07 14:18 ` Pallipadi, Venkatesh
2008-01-07 15:06 ` Mark Lord
2008-01-07 19:12 ` Len Brown
2008-01-07 21:33 ` Mark Lord
2008-01-07 22:43 ` Len Brown
2007-12-01 10:17 ` Andrew Morton
2007-12-01 16:30 ` Arjan van de Ven
2007-12-05 11:17 ` Pavel Machek
2007-12-07 21:38 ` Pallipadi, Venkatesh
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