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* Realtime Preemption, 2.6.12, Beginners Guide?
@ 2005-07-06 11:57 Alistair John Strachan
  2005-07-06 12:51 ` Alistair John Strachan
  2005-07-06 13:31 ` Ingo Molnar
  0 siblings, 2 replies; 101+ messages in thread
From: Alistair John Strachan @ 2005-07-06 11:57 UTC (permalink / raw)
  To: linux-kernel, Ingo Molnar

Hi,

Today I decided to try Ingo's rt-preempt patch on 2.6.12 (V0.7.51-02). I'm 
most interested in the CONFIG_PREEMPT_RT mode, so I selected this option 
instead of the others. I enabled a couple of the debugging options, but I 
wasn't totally clear on which options are most useful, so I just enabled the 
ones that didn't have a warning about significant overhead, namely..

CONFIG_DETECT_SOFTLOCKUP=y
CONFIG_WAKEUP_TIMING=y
CONFIG_CRITICAL_TIMING=y
CONFIG_LATENCY_TIMING=y

Additionally (by mistake) I enabled:

CONFIG_CRITICAL_IRQSOFF_TIMING=y

Which does mention overhead.

Which debugging options are most useful for testing purposes? Is what I've 
selected enough? Also, I got a few unexpected messages in dmesg on bootup. 
Firstly;

spawn_desched_task(00000000)
desched cpu_callback 3/00000000
ksoftirqd started up.
softirq RT prio: 24.
ksoftirqd started up.
softirq RT prio: 24.
[...]
desched cpu_callback 2/00000000
desched thread 0 started up.
softlockup thread 0 started up.

Why does it print out the same ksoftirqd message six times? Is this expected 
behaviour? Next, I got a warning about CONFIG_CRITICAL_IRQSOFF_TIMING;
should this option be enabled?

Finally, I got this:

BUG: soft lockup detected on CPU#0!
 [<c013d7e9>] softlockup_tick+0x89/0xb0 (8)
 [<c0108590>] timer_interrupt+0x50/0xf0 (20)
 [<c013da91>] handle_IRQ_event+0x81/0x100 (16)
 [<c013dbfc>] __do_IRQ+0xec/0x190 (48)
 [<c0105a28>] do_IRQ+0x48/0x70 (40)
 =======================
 [<c024df3b>] acpi_processor_idle+0x0/0x258 (8)
 [<c0103d03>] common_interrupt+0x1f/0x24 (12)
 [<c024df3b>] acpi_processor_idle+0x0/0x258 (4)
 [<c024e05e>] acpi_processor_idle+0x123/0x258 (40)
 [<c024df3b>] acpi_processor_idle+0x0/0x258 (32)
 [<c0101116>] cpu_idle+0x56/0x80 (16)
 [<c03a486c>] start_kernel+0x17c/0x1c0 (12)
 [<c03a43b0>] unknown_bootoption+0x0/0x1f0 (20)

I think it's when my scripts try to set up the IrDA port; the script runs the 
following (I have a weird broken NC6000 IrDA port which needs messing around 
with to work)..

/usr/bin/smcinit -v -s 0x3E8 -f 0x130 -i 4 -d 3 >/dev/null

Of course, the message could've just been coincidental, as it doesn't actually 
refer to the smcs driver at all.

I set preempt_max_latency to zero, but the only messages I've got back from 
the kernel so far are:

( softirq-timer/0-3    |#0): new 3 us maximum-latency wakeup.
( softirq-timer/0-3    |#0): new 1003 us maximum-latency wakeup.
( softirq-timer/0-3    |#0): new 1001 us maximum-latency wakeup.

Which is presumably a good sign.

-- 
Cheers,
Alistair.

personal:   alistair()devzero!co!uk
university: s0348365()sms!ed!ac!uk
student:    CS/CSim Undergraduate
contact:    1F2 55 South Clerk Street,
            Edinburgh. EH8 9PP.

^ permalink raw reply	[flat|nested] 101+ messages in thread
[parent not found: <20050713063310.GA12661@elte.hu>]

end of thread, other threads:[~2005-07-19 22:57 UTC | newest]

Thread overview: 101+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-07-06 11:57 Realtime Preemption, 2.6.12, Beginners Guide? Alistair John Strachan
2005-07-06 12:51 ` Alistair John Strachan
2005-07-06 13:39   ` Ingo Molnar
2005-07-06 15:58     ` Alistair John Strachan
2005-07-06 16:28       ` Ingo Molnar
2005-07-06 16:31         ` Alistair John Strachan
2005-07-06 13:31 ` Ingo Molnar
2005-07-06 15:55   ` Alistair John Strachan
2005-07-06 16:24     ` Ingo Molnar
2005-07-06 16:37       ` Alistair John Strachan
2005-07-06 16:56         ` Alistair John Strachan
2005-07-06 17:01           ` Ingo Molnar
2005-07-06 17:14             ` Alistair John Strachan
2005-07-06 17:27               ` Ingo Molnar
2005-07-06 18:23                 ` Alistair John Strachan
2005-07-06 18:38                   ` Ingo Molnar
2005-07-06 18:41                     ` Ingo Molnar
2005-07-06 19:47                       ` Alistair John Strachan
2005-07-06 20:44                         ` Ingo Molnar
2005-07-06 21:00                           ` Alistair John Strachan
2005-07-06 21:02                             ` Ingo Molnar
2005-07-06 22:15                               ` Alistair John Strachan
2005-07-06 23:08                                 ` Fernando Lopez-Lezcano
2005-07-07  6:04                                   ` Michal Schmidt
2005-07-07 10:25                                     ` Ingo Molnar
2005-07-07  9:46                           ` Alistair John Strachan
2005-07-07 11:21                             ` Alistair John Strachan
2005-07-07 11:29                               ` Ingo Molnar
2005-07-07 11:37                                 ` Alistair John Strachan
2005-07-07 11:42                                   ` Ingo Molnar
2005-07-07 12:15                                     ` Alistair John Strachan
2005-07-07 12:29                                       ` Ingo Molnar
2005-07-07 13:38                                         ` Alistair John Strachan
2005-07-07 12:33                                       ` Alistair John Strachan
2005-07-08  9:47                                     ` Alistair John Strachan
2005-07-08 11:46                                       ` Ingo Molnar
2005-07-08 18:38                                         ` Alistair John Strachan
2005-07-08 19:12                                           ` USB storage does not work with 3GB of RAM, but does with 2G of RAM Jon Schindler
2005-07-08 19:25                                           ` Realtime Preemption, 2.6.12, Beginners Guide? Ingo Molnar
2005-07-08 19:31                                           ` Ingo Molnar
2005-07-08 19:34                                             ` Ingo Molnar
2005-07-08 19:48                                           ` Ingo Molnar
2005-07-08 19:55                                             ` Alistair John Strachan
2005-07-08 20:45                                             ` Alistair John Strachan
2005-07-09 11:58                                               ` Ingo Molnar
2005-07-09 14:07                                                 ` Alistair John Strachan
2005-07-09 14:55                                                   ` Ingo Molnar
2005-07-09 15:57                                                   ` Ingo Molnar
2005-07-09 16:02                                                     ` Ingo Molnar
2005-07-09 16:04                                                     ` Alistair John Strachan
2005-07-11 13:55                                                       ` Alistair John Strachan
2005-07-11 14:12                                                         ` Ingo Molnar
2005-07-11 14:16                                                           ` Ingo Molnar
2005-07-11 14:38                                                             ` Alistair John Strachan
2005-07-11 14:43                                                               ` Ingo Molnar
2005-07-11 15:50                                                                 ` Alistair John Strachan
2005-07-13 14:45                                                                   ` Ingo Molnar
2005-07-13 15:30                                                                     ` Ingo Molnar
2005-07-14 19:58                                                                       ` Alistair John Strachan
2005-07-14 20:16                                                                         ` Lee Revell
2005-07-15 22:12                                                                           ` Alistair John Strachan
2005-07-12  2:56                                                               ` Lee Revell
2005-07-11 15:07                                                             ` Ingo Molnar
2005-07-12 20:09                                                               ` Lee Revell
2005-07-12 21:01                                                                 ` Chuck Harding
2005-07-13 10:39                                                                   ` Ingo Molnar
2005-07-13 12:29                                                                     ` Gene Heskett
2005-07-13 14:01                                                                     ` K.R. Foley
2005-07-13 19:41                                                                       ` Chuck Harding
2005-07-13 19:45                                                                         ` Ingo Molnar
2005-07-14 13:39                                                                           ` K.R. Foley
2005-07-14 12:50                                                                       ` Karsten Wiese
2005-07-14 13:56                                                                         ` K.R. Foley
2005-07-14 14:10                                                                           ` K.R. Foley
2005-07-14 14:11                                                                             ` K.R. Foley
2005-07-14 19:49                                                                         ` Chuck Harding
2005-07-16 17:15                                                                         ` Ingo Molnar
2005-07-16 19:01                                                                           ` K.R. Foley
2005-07-17 12:07                                                                           ` Karsten Wiese
2005-07-18 15:46                                                                             ` K.R. Foley
2005-07-19 11:14                                                                             ` Karsten Wiese
2005-07-19 13:35                                                                               ` Gene Heskett
2005-07-19 13:57                                                                               ` Ingo Molnar
2005-07-19 15:19                                                                                 ` Gene Heskett
2005-07-19 23:00                                                                                   ` Karsten Wiese
2005-07-09 12:41                                               ` Ingo Molnar
2005-07-09 12:46                                                 ` Ingo Molnar
2005-07-09 13:05                                                 ` Ingo Molnar
2005-07-11 22:48                                                   ` William Weston
2005-07-12 13:53                                                     ` Ingo Molnar
2005-07-09 13:13                                                 ` Ingo Molnar
2005-07-09 13:26                                                 ` Ingo Molnar
2005-07-10 19:01                                                   ` PCMCIA stack reduction patch [Was: Re: Realtime Preemption, 2.6.12, Beginners Guide?] Dominik Brodowski
2005-07-09 13:36                                                 ` Realtime Preemption, 2.6.12, Beginners Guide? Ingo Molnar
2005-07-11 13:28                                                 ` Paulo Marques
2005-07-08 11:48                                       ` Ingo Molnar
2005-07-08 17:42                                         ` Alistair John Strachan
2005-07-08 17:48                                           ` Jakub Jelinek
2005-07-08 18:12                                             ` Alistair John Strachan
     [not found] <20050713063310.GA12661@elte.hu>
2005-07-13 10:30 ` karsten wiese
2005-07-13 18:38   ` Chuck Harding

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