From: Adrian Bunk <hidden> Date: 2007-02-26 22:05:24
This email lists some known regressions in 2.6.21-rc1 compared to 2.6.20
that are not yet fixed in Linus' tree.
If you find your name in the Cc header, you are either submitter of one
of the bugs, maintainer of an affectected subsystem or driver, a patch
of you caused a breakage or I'm considering you in any other way possibly
involved with one or more of these issues.
Due to the huge amount of recipients, please trim the Cc when answering.
Subject : forcedeth no longer works
References : http://bugzilla.kernel.org/show_bug.cgi?id=8090
Submitter : David P. Reed [off-list ref]
Caused-By : Ayaz Abdulla [off-list ref]
Status : unknown
Subject : forcedeth: skb_over_panic
References : http://bugzilla.kernel.org/show_bug.cgi?id=8058
Submitter : Albert Hopkins [off-list ref]
Status : unknown
Subject : natsemi ethernet card not detected correctly
References : http://lkml.org/lkml/2007/2/23/4http://lkml.org/lkml/2007/2/23/7
Submitter : Bob Tracy [off-list ref]
Caused-By : Mark Brown [off-list ref]
Handled-By : Mark Brown [off-list ref]
Patch : http://lkml.org/lkml/2007/2/23/142
Status : patch available
Subject : ThinkPad T60: system doesn't come out of suspend to RAM
(CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/22/391
Submitter : Michael S. Tsirkin [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : unknown
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
Subject : i386: no boot with nmi_watchdog=1 (clockevents)
References : http://lkml.org/lkml/2007/2/21/208
Submitter : Daniel Walker [off-list ref]
Caused-By : Thomas Gleixner [off-list ref]
commit e9e2cdb412412326c4827fc78ba27f410d837e6e
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
From: Thomas Gleixner <hidden> Date: 2007-02-27 08:21:50
Adrian,
On Mon, 2007-02-26 at 23:05 +0100, Adrian Bunk wrote:
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
The BUG_ON() was replaced by a warning printk(). The BUG_ON() exposed a
problem with the SMT scheduler. See below.
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
From: Michal Piotrowski <hidden> Date: 2007-02-27 08:35:07
Thomas Gleixner napisał(a):
Adrian,
On Mon, 2007-02-26 at 23:05 +0100, Adrian Bunk wrote:
quoted
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
The BUG_ON() was replaced by a warning printk(). The BUG_ON() exposed a
problem with the SMT scheduler. See below.
quoted
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
From: Michal Piotrowski <hidden> Date: 2007-02-27 08:37:12
Michal Piotrowski napisał(a):
Thomas Gleixner napisał(a):
quoted
Adrian,
On Mon, 2007-02-26 at 23:05 +0100, Adrian Bunk wrote:
quoted
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
The BUG_ON() was replaced by a warning printk(). The BUG_ON() exposed a
problem with the SMT scheduler. See below.
quoted
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
Patch available, not confirmed yet.
I can confirm that the bug is fixed (over 20 hours of testing should be enough).
Adrian,
On Mon, 2007-02-26 at 23:05 +0100, Adrian Bunk wrote:
quoted
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
The BUG_ON() was replaced by a warning printk(). The BUG_ON() exposed a
problem with the SMT scheduler. See below.
quoted
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
Patch available, not confirmed yet.
I can confirm that the bug is fixed (over 20 hours of testing should
be enough).
thanks alot! I think this thing was a long-term performance/latency
regression in HT scheduling as well.
Ingo
From: Mike Galbraith <hidden> Date: 2007-02-27 08:54:26
On Tue, 2007-02-27 at 09:33 +0100, Ingo Molnar wrote:
* Michal Piotrowski [off-list ref] wrote:
quoted
Thomas Gleixner napisał(a):
quoted
Adrian,
On Mon, 2007-02-26 at 23:05 +0100, Adrian Bunk wrote:
quoted
Subject : kernel BUG at kernel/time/tick-sched.c:168 (CONFIG_NO_HZ)
References : http://lkml.org/lkml/2007/2/16/346
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Status : problem is being debugged
The BUG_ON() was replaced by a warning printk(). The BUG_ON() exposed a
problem with the SMT scheduler. See below.
quoted
Subject : BUG: soft lockup detected on CPU#0
NOHZ: local_softirq_pending 20 (SMT scheduler)
References : http://lkml.org/lkml/2007/2/20/257
Submitter : Michal Piotrowski [off-list ref]
Handled-By : Thomas Gleixner [off-list ref]
Ingo Molnar [off-list ref]
Status : problem is being debugged
Patch available, not confirmed yet.
I can confirm that the bug is fixed (over 20 hours of testing should
be enough).
thanks alot! I think this thing was a long-term performance/latency
regression in HT scheduling as well.
Agreed.
I was recently looking at that spot because I found that niced tasks
were taking latency hits, and disabled it, which helped a bunch. I also
can't understand why it would be OK to interleave a normal task with an
RT task sometimes, but not others.. that's meaningless to the RT task.
IMHO, SMT scheduling should be a buyer beware thing. Maximizing your
core utilization comes at a price, but so does disabling it, so I think
letting the user decide what he wants is the right thing to do.
-Mike