2.6.27-rc8-git7: Reported regressions from 2.6.26

2.6.27-rc8-git7: Reported regressions from 2.6.26

[Rafael J. Wysocki]

This message contains a list of some regressions from 2.6.26, for which there
are no fixes in the mainline I know of.  If any of them have been fixed already,
please let me know.

If you know of any other unresolved regressions from 2.6.26, please let me know
either and I'll add them to the list.  Also, please let me know if any of the
entries below are invalid.

Each entry from the list will be sent additionally in an automatic reply to
this message with CCs to the people involved in reporting and handling the
issue.


Listed regressions statistics:

  Date          Total  Pending  Unresolved
  ----------------------------------------
  2008-10-04      181       41          33
  2008-09-27      173       35          28
  2008-09-21      169       45          36
  2008-09-15      163       46          32
  2008-09-12      163       51          38
  2008-09-07      150       43          33
  2008-08-30      135       48          36
  2008-08-23      122       48          40
  2008-08-16      103       47          37
  2008-08-10       80       52          31
  2008-08-02       47       31          20


Unresolved regressions
----------------------

Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11700
Subject		: ACPI instabilities and IRQs being disabled
Submitter	: Shawn Starr <shawn.starr@rogers.com>
Date		: 2008-09-27 22:40 (8 days old)
References	: http://marc.info/?l=linux-kernel&m=122255527412178&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11699
Subject		: 2.6.27-rc-7: BUG: scheduling while atomic, c1e_idle+0x98/0xe0
Submitter	: Prakash Punnoor <prakash@punnoor.de>
Date		: 2008-09-28 17:45 (7 days old)
References	: http://marc.info/?l=linux-kernel&m=122262403415629&w=4
Handled-By	: Thomas Gleixner <tglx@linutronix.de>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11698
Subject		: 2.6.27-rc7, freezes with &gt; 1 s2ram cycle
Submitter	: Soeren Sonnenburg <kernel@nn7.de>
Date		: 2008-09-29 11:29 (6 days old)
References	: http://marc.info/?l=linux-kernel&m=122268780926859&w=4
Handled-By	: Rafael J. Wysocki <rjw@sisk.pl>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11697
Subject		: CD tray closes spontaneously after opening it
Submitter	: Frans Pop <elendil@planet.nl>
Date		: 2008-09-30 10:47 (5 days old)
References	: http://marc.info/?l=linux-kernel&m=122277167125264&w=4
Handled-By	: Kay Sievers <kay.sievers@vrfy.org>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11695
Subject		: USB disconnects every 30 seconds
Submitter	: Dave Hansen <dave@sr71.net>
Date		: 2008-10-03 17:45 (2 days old)
References	: http://marc.info/?l=linux-kernel&m=122305738430115&w=4
Handled-By	: Alan Stern <stern@rowland.harvard.edu>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11676
Subject		: 2.6.27-rc2 to rc8, apgart fails, iommu=soft works, regression
Submitter	: Duncan <1i5t5.duncan@cox.net>
Date		: 2008-09-30 10:24 (5 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11664
Subject		: acpi errors and random freeze on sony vaio sr
Submitter	: Giovanni Pellerano <giovanni.pellerano@gmail.com>
Date		: 2008-09-28 03:48 (7 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11643
Subject		: ALSA sound/core/pcm_native.c:1947: BUG? (err &gt;= 0)
Submitter	: sangu <sangu.gnome@gmail.com>
Date		: 2008-09-24 16:51 (11 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11634
Subject		: Sometime my laptop is dead on resume from ram
Submitter	: Romano Giannetti <romano.giannetti@gmail.com>
Date		: 2008-09-24 01:12 (11 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11608
Subject		: 2.6.27-rc6 BUG: unable to handle kernel paging request
Submitter	: John Daiker <daikerjohn@gmail.com>
Date		: 2008-09-16 23:00 (19 days old)
References	: http://marc.info/?l=linux-kernel&m=122160611517267&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11607
Subject		: 2.6.27-rc6  Bug in tty_chars_in_buffer
Submitter	: John Daiker <daikerjohn@gmail.com>
Date		: 2008-09-15 2:26 (20 days old)
References	: http://marc.info/?l=linux-kernel&m=122144565514490&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11569
Subject		: Don't complain about disabled irqs when the system has paniced
Submitter	: Andi Kleen <andi@firstfloor.org>
Date		: 2008-09-02 13:49 (33 days old)
References	: http://marc.info/?l=linux-kernel&m=122036356127282&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11568
Subject		: spontaneous reboot on resume with 2.6.27
Submitter	: Andy Wettstein <ajw1980@gmail.com>
Date		: 2008-09-14 20:00 (21 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11543
Subject		: kernel panic: softlockup in tick_periodic() ???
Submitter	: Joshua Hoblitt <j_kernel@hoblitt.com>
Date		: 2008-09-11 16:46 (24 days old)
References	: http://marc.info/?l=linux-kernel&m=122117786124326&w=4
Handled-By	: Thomas Gleixner <tglx@linutronix.de>
		  Cyrill Gorcunov <gorcunov@gmail.com>
		  Ingo Molnar <mingo@elte.hu>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11516
Subject		: severe performance degradation on x86_64 going from 2.6.26-rc9 -&gt; 2.6.27-rc5
Submitter	: Jason Vas Dias <jason.vas.dias@gmail.com>
Date		: 2008-09-07 13:59 (28 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11512
Subject		: sort-of regression due to "kconfig: speed up all*config + randconfig"
Submitter	: Alexey Dobriyan <adobriyan@gmail.com>
Date		: 2008-09-05 22:50 (30 days old)
References	: http://marc.info/?l=linux-kernel&m=122065498013858&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11504
Subject		: reiserfs  BUG in 2.6.27-rc5
Submitter	: Randy Dunlap <randy.dunlap@oracle.com>
Date		: 2008-09-03 16:35 (32 days old)
References	: http://marc.info/?l=linux-kernel&m=122045982120138&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11476
Subject		: failure to associate after resume from suspend to ram
Submitter	: Michael S. Tsirkin <m.s.tsirkin@gmail.com>
Date		: 2008-09-01 13:33 (34 days old)
References	: http://marc.info/?l=linux-kernel&m=122028529415108&w=4
Handled-By	: Zhu Yi <yi.zhu@intel.com>
		  Dan Williams <dcbw@redhat.com>
		  Jouni Malinen <j@w1.fi>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11407
Subject		: suspend: unable to handle kernel paging request
Submitter	: Vegard Nossum <vegard.nossum@gmail.com>
Date		: 2008-08-21 17:28 (45 days old)
References	: http://marc.info/?l=linux-kernel&m=121933974928881&w=4
Handled-By	: Rafael J. Wysocki <rjw@sisk.pl>
		  Pekka Enberg <penberg@cs.helsinki.fi>
		  Pavel Machek <pavel@suse.cz>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11404
Subject		: BUG: in 2.6.23-rc3-git7 in do_cciss_intr
Submitter	: rdunlap <randy.dunlap@oracle.com>
Date		: 2008-08-21 5:52 (45 days old)
References	: http://marc.info/?l=linux-kernel&m=121929819616273&w=4
		  http://marc.info/?l=linux-kernel&m=121932889105368&w=4
Handled-By	: Miller, Mike (OS Dev) <Mike.Miller@hp.com>
		  James Bottomley <James.Bottomley@hansenpartnership.com>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11380
Subject		: lockdep warning: cpu_add_remove_lock at:cpu_maps_update_begin+0x14/0x16
Submitter	: Ingo Molnar <mingo@elte.hu>
Date		: 2008-08-20 6:44 (46 days old)
References	: http://marc.info/?l=linux-kernel&m=121921480931970&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11340
Subject		: LTP overnight run resulted in unusable box
Submitter	: Alexey Dobriyan <adobriyan@gmail.com>
Date		: 2008-08-13 9:24 (53 days old)
References	: http://marc.info/?l=linux-kernel&m=121861951902949&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11308
Subject		: tbench regression on each kernel release from 2.6.22 -&gt; 2.6.28
Submitter	: Christoph Lameter <cl@linux-foundation.org>
Date		: 2008-08-11 18:36 (55 days old)
References	: http://marc.info/?l=linux-kernel&m=121847986119495&w=4
		  http://marc.info/?l=linux-kernel&m=122125737421332&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11272
Subject		: BUG: parport_serial in 2.6.27-rc1 for NetMos Technology PCI 9835
Submitter	: Jaswinder Singh <jaswinderlinux@gmail.com>
Date		: 2008-08-05 15:12 (61 days old)
References	: http://marc.info/?l=linux-kernel&m=121794900319776&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11271
Subject		: BUG: fealnx in 2.6.27-rc1
Submitter	: Jaswinder Singh <jaswinderlinux@gmail.com>
Date		: 2008-08-05 14:58 (61 days old)
References	: http://marc.info/?l=linux-netdev&m=121794762016830&w=4
		  http://lkml.org/lkml/2008/8/10/98
Handled-By	: Francois Romieu <romieu@fr.zoreil.com>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11264
Subject		: Invalid op opcode in kernel/workqueue
Submitter	: Jean-Luc Coulon <jean.luc.coulon@gmail.com>
Date		: 2008-08-07 04:18 (59 days old)


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11230
Subject		: Kconfig no longer outputs a .config with freshly updated defconfigs
Submitter	: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Date		: 2008-08-02 16:03 (64 days old)
References	: http://marc.info/?l=linux-kernel&m=121769306319391&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11224
Subject		: Only three cores found on quad-core machine.
Submitter	: Dave Jones <davej@redhat.com>
Date		: 2008-08-01 18:15 (65 days old)
References	: http://marc.info/?l=linux-kernel&m=121761475224719&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11220
Subject		: Screen stays black after resume
Submitter	: Nico Schottelius <nico@schottelius.org>
Date		: 2008-07-31 21:05 (66 days old)
References	: http://marc.info/?l=linux-kernel&m=121753882422899&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11215
Subject		: INFO: possible recursive locking detected ps2_command
Submitter	: Zdenek Kabelac <zdenek.kabelac@gmail.com>
Date		: 2008-07-31 9:41 (66 days old)
References	: http://marc.info/?l=linux-kernel&m=121749737011637&w=4
Handled-By	: Peter Zijlstra <a.p.zijlstra@chello.nl>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11210
Subject		: libata badness
Submitter	: Kumar Gala <galak@kernel.crashing.org>
Date		: 2008-07-31 18:53 (66 days old)
References	: http://marc.info/?l=linux-ide&m=121753059307310&w=4
Handled-By	: Kumar Gala <galak@kernel.crashing.org>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11209
Subject		: 2.6.27-rc1 process time accounting
Submitter	: Lukas Hejtmanek <xhejtman@ics.muni.cz>
Date		: 2008-07-31 10:43 (66 days old)
References	: http://marc.info/?l=linux-kernel&m=121750102917490&w=4
		  http://lkml.org/lkml/2008/9/30/199
Handled-By	: Peter Zijlstra <a.p.zijlstra@chello.nl>


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11207
Subject		: VolanoMark regression with 2.6.27-rc1
Submitter	: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Date		: 2008-07-31 3:20 (66 days old)
References	: http://marc.info/?l=linux-kernel&m=121747464114335&w=4
Handled-By	: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
		  Peter Zijlstra <a.p.zijlstra@chello.nl>
		  Dhaval Giani <dhaval@linux.vnet.ibm.com>
		  Miao Xie <miaox@cn.fujitsu.com>


Regressions with patches
------------------------

Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11701
Subject		: sky2 wol regression
Submitter	: Tino Keitel <tino.keitel@gmx.de>
Date		: 2008-09-24 8:05 (11 days old)
References	: http://marc.info/?l=linux-kernel&m=122224359222164&w=4
Handled-By	: Rafael J. Wysocki <rjw@sisk.pl>
Patch		: http://marc.info/?l=linux-kernel&m=122298334522551&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11696
Subject		: 2.6.27-rc8 doubled times
Submitter	: Hugh Dickins <hugh@veritas.com>
Date		: 2008-10-03 10:21 (2 days old)
References	: http://marc.info/?l=linux-kernel&m=122302939313636&w=4
Handled-By	: Thomas Gleixner <tglx@linutronix.de>
Patch		: http://marc.info/?l=linux-kernel&m=122307260621434&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11629
Subject		: quad G5 fails to shut down
Submitter	: Johannes Berg <johannes@sipsolutions.net>
Date		: 2008-09-23 14:20 (12 days old)
Handled-By	: Johannes Berg <johannes@sipsolutions.net>
Patch		: http://bugzilla.kernel.org/show_bug.cgi?id=11629#c8


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11615
Subject		: sata_nv EH problems
Submitter	: Pär Andersson <paran@lysator.liu.se>
Date		: 2008-09-21 18:09 (14 days old)
Handled-By	: Tejun Heo <tj@kernel.org>
Patch		: http://bugzilla.kernel.org/attachment.cgi?id=18078&action=view


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11550
Subject		: pnp: Huge number of "io resource overlap" messages
Submitter	: Frans Pop <elendil@planet.nl>
Date		: 2008-09-09 10:50 (26 days old)
References	: http://marc.info/?l=linux-kernel&m=122095745403793&w=4
Handled-By	: Rene Herman <rene.herman@keyaccess.nl>
		  Bjorn Helgaas <bjorn.helgaas@hp.com>
Patch		: http://marc.info/?l=linux-kernel&m=122246533505643&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11549
Subject		: 2.6.27-rc5 acpi: EC Storm error message on bootup
Submitter	: <jmerkey@wolfmountaingroup.com>
Date		: 2008-09-02 21:27 (33 days old)
References	: http://marc.info/?l=linux-kernel&m=122039255517586&w=4
Handled-By	: Alexey Starikovskiy <astarikovskiy@suse.de>
Patch		: http://bugzilla.kernel.org/attachment.cgi?id=18047&action=view


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11505
Subject		: oltp ~10% regression with 2.6.27-rc5 on stoakley machine
Submitter	: Lin Ming <ming.m.lin@intel.com>
Date		: 2008-09-04 7:06 (31 days old)
References	: http://marc.info/?l=linux-kernel&m=122051202202373&w=4
		  http://marc.info/?t=122089704700005&r=1&w=4
Handled-By	: Peter Zijlstra <a.p.zijlstra@chello.nl>
		  Gregory Haskins <ghaskins@novell.com>
		  Ingo Molnar <mingo@elte.hu>
Patch		: http://marc.info/?l=linux-kernel&m=122194673932703&w=4


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11442
Subject		: btusb hibernation/suspend breakage in current -git
Submitter	: Rafael J. Wysocki <rjw@sisk.pl>
Date		: 2008-08-25 11:37 (41 days old)
References	: http://marc.info/?l=linux-bluetooth&m=121966402012074&w=4
Handled-By	: Oliver Neukum <oliver@neukum.org>
Patch		: http://marc.info/?l=linux-bluetooth&m=121967226027323&w=4
		  http://bugzilla.kernel.org/show_bug.cgi?id=11442#c1


For details, please visit the bug entries and follow the links given in
references.

As you can see, there is a Bugzilla entry for each of the listed regressions.
There also is a Bugzilla entry used for tracking the regressions from 2.6.26,
unresolved as well as resolved, at:

http://bugzilla.kernel.org/show_bug.cgi?id=11167

Please let me know if there are any Bugzilla entries that should be added to
the list in there.

Thanks,
Rafael

Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26

[Evgeniy Polyakov]

Hi.

On Sat, Oct 04, 2008 at 07:28:42PM +0200, Rafael J. Wysocki (rjw-KKrjLPT3xs0@public.gmane.org) wrote:
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11308
> Subject		: tbench regression on each kernel release from 2.6.22 -> 2.6.28
> Submitter	: Christoph Lameter <cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
> Date		: 2008-08-11 18:36 (55 days old)
> References	: http://marc.info/?l=linux-kernel&m=121847986119495&w=4
> 		  http://marc.info/?l=linux-kernel&m=122125737421332&w=4

Just for the reference, this one regresses from the 2.6.23. Particular
2.6.26-27 part can be partially fixed by disabling TSO/GSO, since tbench
workload issues quite small packets, and system has no time to
incorporate them into particulary big TSO/GSO frame to get advantage of
this technology. The most noticeble perfromance drop was between 23 and
24 kernels. I work on this issue.
 
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11207
> Subject		: VolanoMark regression with 2.6.27-rc1
> Submitter	: Zhang, Yanmin <yanmin_zhang-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> Date		: 2008-07-31 3:20 (66 days old)
> References	: http://marc.info/?l=linux-kernel&m=121747464114335&w=4
> Handled-By	: Zhang, Yanmin <yanmin_zhang-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> 		  Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
> 		  Dhaval Giani <dhaval-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> 		  Miao Xie <miaox-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>

This one is different, but any other benchmark related to network over
loopback (and in some case over other media) performance degradation
should be very likely handled by the above case.

-- 
	Evgeniy Polyakov

Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26

[Rafael J. Wysocki]

On Sunday, 5 of October 2008, Evgeniy Polyakov wrote:
> Hi.
> 
> On Sat, Oct 04, 2008 at 07:28:42PM +0200, Rafael J. Wysocki (rjw-KKrjLPT3xs0@public.gmane.org) wrote:
> > Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11308
> > Subject		: tbench regression on each kernel release from 2.6.22 -> 2.6.28
> > Submitter	: Christoph Lameter <cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
> > Date		: 2008-08-11 18:36 (55 days old)
> > References	: http://marc.info/?l=linux-kernel&m=121847986119495&w=4
> > 		  http://marc.info/?l=linux-kernel&m=122125737421332&w=4
> 
> Just for the reference, this one regresses from the 2.6.23.

Still, tbench results from 2.6.26 are better than from 2.6.27-rc.
That's why it's still on the list, but if you think that's not relevant, please
let me know and I'll drop it.

Thanks,
Rafael

Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26

[Herbert Xu]

Rafael J. Wysocki <rjw-KKrjLPT3xs0@public.gmane.org> wrote:
>> > Bug-Entry   : http://bugzilla.kernel.org/show_bug.cgi?id=11308
>> > Subject             : tbench regression on each kernel release from 2.6.22 -&gt; 2.6.28
>> > Submitter   : Christoph Lameter <cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
>> > Date                : 2008-08-11 18:36 (55 days old)
>> > References  : http://marc.info/?l=linux-kernel&m=121847986119495&w=4
>> >               http://marc.info/?l=linux-kernel&m=122125737421332&w=4
>> 
>> Just for the reference, this one regresses from the 2.6.23.
> 
> Still, tbench results from 2.6.26 are better than from 2.6.27-rc.
> That's why it's still on the list, but if you think that's not relevant, please
> let me know and I'll drop it.

Note that 2.6.27 beats 2.6.26 by 30% with bulk traffic over
loopback as opposed to the small packets sent by tbench where
I saw a 5% drop in performance on my machine.

So I'm not sure whether this should really be classified as
a regression if we limit ourselves to the changes between 26
and 27.

The changes prior to 26 seem to be more significant.

Chyeers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26

[Evgeniy Polyakov]

On Sun, Oct 05, 2008 at 01:02:20PM +0200, Rafael J. Wysocki (rjw-KKrjLPT3xs0@public.gmane.org) wrote:
> > Just for the reference, this one regresses from the 2.6.23.
> 
> Still, tbench results from 2.6.26 are better than from 2.6.27-rc.
> That's why it's still on the list, but if you think that's not relevant, please
> let me know and I'll drop it.

I meant it continuously regresses from .23 including 26-27 timeframe.
There were at least two changes in 26-27 which caused tbench regression
in this particular time interval. One of them enabled TSO over loopback
by default, so one can turn it off via ethtools or this patch:
http://marc.info/?l=linux-netdev&m=122263663631600&w=2

another (hopefully) one I'm trying to find out, which is a bit complex
and slow, since e1000 driver changes in the middle of the 26-27
timeframe does not allow my testing machines to boot.

So, there is a regression (partially resolved), but it is only part of
the problem.

-- 
	Evgeniy Polyakov

Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26

[Evgeniy Polyakov]

Hi.

On Sun, Oct 05, 2008 at 07:49:31PM +0800, Herbert Xu (herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org) wrote:
> Note that 2.6.27 beats 2.6.26 by 30% with bulk traffic over
> loopback as opposed to the small packets sent by tbench where
> I saw a 5% drop in performance on my machine.
> 
> So I'm not sure whether this should really be classified as
> a regression if we limit ourselves to the changes between 26
> and 27.
> 
> The changes prior to 26 seem to be more significant.

Yes, that's the point, TSO over loopback for big packets or workload
where there packets can be easily combined into big one results in a
fair performance improvement, but for small packets it regresses about
5-10 %. And yes, there are yet unresolved changes which caused bigger
performance degradation.

-- 
	Evgeniy Polyakov