Re: 2.6.13-rc6-rt3

Re: 2.6.13-rc6-rt3

[Andrew Burgess]

>I haven't used any of the RT patches since V0.7.51-xx, but I upgraded to -rt8 
>yesterday and had a couple of problems. I've just noticed you released -rt9, 
>but I don't think my problem is listed as fixed.. I'll upgrade anyway, in a 
>minute.

>The problem I'm having is that when the kernel probes my IDE devices it slows 
>down, taking ages to complete the probe. Henceforth the kernel seems to work 
>at a slower speed doing just about anything (compiling, etc.), but 
>interactive performance is okay. It's a bizarre problem.

Similar symptoms happened to me recently and it turned out I had accidently
omitted support for my mb ide chipset (ata_piix) while shrinking my config so
the kernel was unable to set dma mode. Took me a while to find because everything
was working (in PIO mode) just really slowly :-)

Re: 2.6.13-rc6-rt3

[Steven Rostedt]

On Thu, 2005-08-18 at 12:58 -0700, Andrew Burgess wrote:

> Similar symptoms happened to me recently and it turned out I had accidently
> omitted support for my mb ide chipset (ata_piix) while shrinking my config so
> the kernel was unable to set dma mode. Took me a while to find because everything
> was working (in PIO mode) just really slowly :-)
> 

[shameless plug]

Here's a good script to really shrink your config and not lose anything.
If you have a lot of modules configured and you want to only compile
those that are used, this perl script will do the job.

-- Steve

http://www.kihontech.com/code/streamline_config.pl

2.6.13-rc6-rt3

[Ingo Molnar]

i have released the 2.6.13-rc6-rt3 tree, which can be downloaded from 
the usual place:

  http://redhat.com/~mingo/realtime-preempt/

Changes since 2.6.13-rc6-rt2:

 - reverted an incorrect tasklist_lock -> lock_task() conversion that 
   slipped in via an earlier hack in the HRT code. The issue it tried to 
   solve is mooted by the RCU-tasklist-lock code.

 - introduce mutex_chprio() as the mechanism for High Resolution timers 
   to dynamically change the priority of the HRT softirq thread. [This
   fixes a latency/priority bug in where the dynamic prio would override 
   the inherited priority, and when the PI mechanism restores priority 
   it would override the HRT priority.]

 - now that HR-timer dynamic priorities have the proper framework, 
   removed the HIGH_RES_TIMERS_DYN_PRIO config option and made the 
   feature unconditional.

to build a 2.6.13-rc6-rt3 tree, the following patches should be applied:

   http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.12.tar.bz2
   http://kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.13-rc6.bz2
   http://redhat.com/~mingo/realtime-preempt/patch-2.6.13-rc6-rt3

	Ingo

Re: 2.6.13-rc6-rt3

[Alistair John Strachan]

On Tuesday 16 August 2005 13:18, Ingo Molnar wrote:
> i have released the 2.6.13-rc6-rt3 tree, which can be downloaded from
> the usual place:
>
>   http://redhat.com/~mingo/realtime-preempt/
>
> Changes since 2.6.13-rc6-rt2:

Ingo,

I haven't used any of the RT patches since V0.7.51-xx, but I upgraded to -rt8 
yesterday and had a couple of problems. I've just noticed you released -rt9, 
but I don't think my problem is listed as fixed.. I'll upgrade anyway, in a 
minute.

The problem I'm having is that when the kernel probes my IDE devices it slows 
down, taking ages to complete the probe. Henceforth the kernel seems to work 
at a slower speed doing just about anything (compiling, etc.), but 
interactive performance is okay. It's a bizarre problem.

Of course, I assumed this was due to the latest timer changes, and so I 
disabled CONFIG_HIGH_RES_TIMERS and went back to CONFIG_HPET_TIMER.
This works perfectly.

For the moment, is it worth debugging problems in the high res timers set or 
are there known (fixable) issues?

-- 
Cheers,
Alistair.

'No sense being pessimistic, it probably wouldn't work anyway.'
Third year Computer Science undergraduate.
1F2 55 South Clerk Street, Edinburgh, UK.

Re: 2.6.13-rc6-rt3

[Thomas Gleixner]

Alistair,

On Thu, 2005-08-18 at 10:57 +0100, Alistair John Strachan wrote:
> The problem I'm having is that when the kernel probes my IDE devices it slows 
> down, taking ages to complete the probe. Henceforth the kernel seems to work 
> at a slower speed doing just about anything (compiling, etc.), but 
> interactive performance is okay. It's a bizarre problem.
> 
> Of course, I assumed this was due to the latest timer changes, and so I 
> disabled CONFIG_HIGH_RES_TIMERS and went back to CONFIG_HPET_TIMER.
> This works perfectly.

Can you please send me your .config which shows the problem ?

tglx