Bug 12417

Summary:	glx performance drop with: "x86: PAT: implement track/untrack of pfnmap regions for x86 - v3"
Product:	Platform Specific/Hardware	Reporter:	Rafael J. Wysocki (rjw)
Component:	x86-64	Assignee:	platform_x86_64 (platform_x86_64)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	brian, venki
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	commit 5899329b19100c0b82dc78e9b21ed8b920c9ffb3	Subsystem:
Regression:	Yes	Bisected commit-id:
Bug Depends on:
Bug Blocks:	12398

Description Rafael J. Wysocki 2009-01-10 16:47:55 UTC

Subject    : [regression] glx performance drop with: "x86: PAT: implement track/untrack of pfnmap regions for x86 - v3"
Submitter  : Alexey Fisher <bug-track@fisher-privat.net>
Date       : 2009-01-06 18:46
References : http://marc.info/?l=linux-kernel&m=123126782822696&w=4
Handled-By : "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>

This entry is being used for tracking a regression from 2.6.28.  Please don't
close it until the problem is fixed in the mainline.

Introduced by:

commit 5899329b19100c0b82dc78e9b21ed8b920c9ffb3
Author: venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>
Date:   Thu Dec 18 11:41:30 2008 -0800

    x86: PAT: implement track/untrack of pfnmap regions for x86 - v3

    Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
    Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
    Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Comment 1 Rafael J. Wysocki 2009-01-10 16:48:19 UTC

First-Bad-Commit : 5899329b19100c0b82dc78e9b21ed8b920c9ffb3

Comment 2 Brian Rogers 2009-01-22 03:18:20 UTC

I just bisected a freeze back to this same commit. On my 64-bit laptop system, any kernel past this commit with PAT enabled will freeze when I VT switch from X to a console, leaving a mostly black image with a few scatterings of text.

Comment 3 Ingo Molnar 2009-01-22 04:02:37 UTC

> I just bisected a freeze back to this same commit. On my 64-bit laptop 
> system, any kernel past this commit with PAT enabled will freeze when I 
> VT switch from X to a console, leaving a mostly black image with a few 
> scatterings of text.

There are a handful of PAT bugs fixed in the -tip tree:

  http://people.redhat.com/mingo/tip.git/README

Could you please double-check whether your box gets fixed by them too?

	Ingo

Comment 4 Brian Rogers 2009-01-22 15:59:13 UTC

VT switching works on tip/master with PAT enabled. Appears to be solved.

Comment 5 Rafael J. Wysocki 2009-02-04 04:19:45 UTC

Handled-By : Ingo Molnar <mingo@elte.hu>

Comment 6 Rafael J. Wysocki 2009-02-04 16:54:30 UTC

On Wednesday 04 February 2009, Alexey Fisher wrote:
> Ingo Molnar schrieb:
> > * Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > 
> >> This message has been generated automatically as a part of a report
> >> of recent regressions.
> >>
> >> The following bug entry is on the current list of known regressions
> >> from 2.6.28.  Please verify if it still should be listed and let me know
> >> (either way).
> >>
> >>
> >> Bug-Entry  : http://bugzilla.kernel.org/show_bug.cgi?id=12417
> >> Subject            : glx performance drop with: "x86: PAT: implement
> track/untrack of pfnmap regions for x86 - v3"
> >> Submitter  : Alexey Fisher <bug-track@fisher-privat.net>
> >> Date               : 2009-01-06 18:46 (30 days old)
> >> First-Bad-Commit:
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=5899329b19100c0b82dc78e9b21ed8b920c9ffb3
> >> References : http://marc.info/?l=linux-kernel&m=123126782822696&w=4
> >> Handled-By : Pallipadi, Venkatesh <venkatesh.pallipadi@intel.com>
> >>              Ingo Molnar <mingo@elte.hu>
> >>
> > 
> > this should be fixed in latest -git. Alexey, can you confirm?
> > 
> >     Ingo
> 
> I confirm it. It working  great with latest git 2.6.29-rc3-00495-gdcf6a79.
>       Alexey