lkml.org 
[lkml]   [2006]   [Apr]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [ANNOUNCE][RFC] PlugSched-6.3.1 for 2.6.16-rc5
Al Boldi wrote:
> Peter Williams wrote:
>> Al Boldi wrote:
>>> Peter Williams wrote:
>>>> Al Boldi wrote:
>>>>> Peter Williams wrote:
>>>>>> Al Boldi wrote:
>>>>>>>>>> Control parameters for the scheduler can be read/set via files
>>>>>>>>>> in:
>>>>>>>>>>
>>>>>>>>>> /sys/cpusched/<scheduler>/
>>>>>>> The default values for spa make it really easy to lock up the
>>>>>>> system.
>>>>>> Which one of the SPA schedulers and under what conditions? I've been
>>>>>> mucking around with these and may have broken something. If so I'd
>>>>>> like to fix it.
>>>>> spa_no_frills, with a malloc-hog less than timeslice. Setting
>>>>> promotion_floor to max unlocks the console.
>>>> OK, you could also try increasing the promotion interval.
>>> Seems that this will only delay the lock in spa_svr but not inhibit it.
>> OK. But turning the promotion mechanism off completely (which is what
>> setting the floor to the maximum) runs the risk of a runaway high
>> priority task locking the whole system up. IMHO the only SPA scheduler
>> where it's safe for the promotion floor to be greater than MAX_RT_PRIO
>> is spa_ebs. So a better solution is highly desirable.
>
> Yes.
>
>> I'd like to fix this problem but don't fully understand what it is.
>> What do you mean by a malloc-hog? Would it possible for you to give me
>> an example of how to reproduce the problem?
>
> Can you try the attached mem-eater passing it the number of kb to be eaten.
>
> i.e. '# while :; do ./eatm 9999 ; done'
>
> This will print the number of bytes eaten and the timing in ms.
>
> Adjust the number of kb to be eaten such that the timing will be less than
> timeslice (120ms by default for spa). Switch to another vt and start
> pressing enter. A console lockup should follow within seconds for all spas
> except ebs.

This doesn't seem to present a problem (other than the eatme loop being
hard to kill with control-C) on my system using spa_ws with standard
settings. I tried both UP and SMP. I may be doing something wrong or
perhaps don't understand what you mean by a console lock up. When you
say "less than the timeslice" how much smaller do you mean?

Peter
PS I even managed to do a kernel build with the eatme loop running on a
single processor system.
--
Peter Williams pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-04-08 03:31    [W:0.104 / U:0.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site