linux-kernel - Re: [Xen-devel] Stop the continuous flood of (XEN) traps.c:2432:d0 Domain attempted WRMSR ..

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Message-ID: <20120328202907.GA1784@phenom.dumpdata.com>
Date:	Wed, 28 Mar 2012 16:29:07 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	Konrad Rzeszutek Wilk <konrad@...nok.org>,
	Pasi K?rkk?inen <pasik@....fi>, mjg@...hat.com,
	linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com
Subject: Re: [Xen-devel] Stop the continuous flood of (XEN) traps.c:2432:d0
 Domain	attempted WRMSR ..

On Thu, Feb 09, 2012 at 01:27:15PM -0800, Jesse Barnes wrote:
> On Thu, 9 Feb 2012 17:21:47 -0400
> Konrad Rzeszutek Wilk <konrad@...nok.org> wrote:
> 
> > On Sun, Feb 05, 2012 at 09:44:13PM +0200, Pasi K?rkk?inen wrote:
> > > On Fri, Feb 03, 2012 at 01:55:27PM -0500, Konrad Rzeszutek Wilk wrote:
> > > > On Fri, Feb 03, 2012 at 08:09:52PM +0200, Pasi K?rkk?inen wrote:
> > > > > Hello,
> > > > > 
> > > > > IIRC there was some discussion earlier about these messages in Xen's dmesg:
> > > > > 
> > > > > (XEN) traps.c:2432:d0 Domain attempted WRMSR 00000000000001ac from 0x0000000000c800c8 to 0x0000000080c880c8.
> > > > > (XEN) traps.c:2432:d0 Domain attempted WRMSR 00000000000001ac from 0x0000000000c800c8 to 0x0000000080c880c8.
> > > > > (XEN) traps.c:2432:d0 Domain attempted WRMSR 00000000000001ac from 0x0000000000c800c8 to 0x0000000080c880c8.
> > > > > (XEN) traps.c:2432:d0 Domain attempted WRMSR 00000000000001ac from 0x0000000000c800c8 to 0x0000000080c880c8.
> > > > > 
> > > > > At least on my systems there's continuous flood of those messages, so they will fill up the
> > > > > Xen dmesg log buffer and "xm dmesg" or "xl dmesg" won't show any valuable information, just those messages.
> > > > 
> > > > Is it always that MSR? That looks to be TURBO_POWER_CURRENT_LIMIT
> > > > which is the intel_ips driver doing.
> > > > 
> > > 
> > > Yeah, it's always the same..
> > > 
> > > > > 
> > > > > I seem to be getting those messages even when there's only dom0 running.
> > > > > Is the plan to drop those messages? What's causing them? 
> > > > 
> > > > Looks to be the intel-ips. If you rename it does the issue disappear?
> > > 
> > > I just did "rmmod intel_ips" and the flood stopped.. 
> > > 
> > > 
> > > Btw on baremetal I get this in dmesg:
> > > 
> > > [  745.033645] CPU1: Core temperature above threshold, cpu clock throttled (total events = 1)
> > > [  745.033652] CPU3: Core temperature above threshold, cpu clock throttled (total events = 1)
> > > [  745.034676] CPU1: Core temperature/speed normal
> > > [  745.034678] CPU3: Core temperature/speed normal
> > > [  849.678508] intel ips 0000:00:1f.6: MCP limit exceeded: Avg temp 9682, limit 9000
> > > [  899.614074] intel ips 0000:00:1f.6: MCP limit exceeded: Avg temp 9896, limit 9000
> > > [  899.722881] [Hardware Error]: Machine check events logged
> > > [ 1172.675987] CPU3: Core temperature above threshold, cpu clock throttled (total events = 78)
> > > [ 1172.675990] CPU1: Core temperature above threshold, cpu clock throttled (total events = 78)
> > > [ 1172.677038] CPU1: Core temperature/speed normal
> > > [ 1172.677042] CPU3: Core temperature/speed normal
> > > [ 1174.260050] intel ips 0000:00:1f.6: MCP limit exceeded: Avg temp 9676, limit 9000
> > > [ 1199.339634] [Hardware Error]: Machine check events logged
> > 
> > Jesse, and Matthew,
> > 
> > Is there a way to make the intel_ips.c driver be in a "low-power" state?
> > 
> > My first thought about fixing this was that we could allow the
> > hypervisor to allow those RDMSR but the Linux kernel has no power to
> > actually influence the power management (as the hypervisor is in charge
> > of that) - so would the driver be capable of just sitting back and
> > not influencing the CPU?
> 
> Yeah it's easy enough to turn off or disable.  But it doesn't currently
> export any knobs for controlling behavior.  I don't have any issue with
> exposing some though...

Pasi,

Could you test the two patches independetly of each other? Meaning
test the Linux one without the Xen one, and vice-versa.



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