[Xenomai] memory allocation performance in kernel ipipe

Stéphane Ancelot sancelot at numalliance.com
Fri Dec 9 16:28:29 CET 2016

Le 08/12/2016 à 08:42, Henning Schild a écrit :
> Am Thu, 8 Dec 2016 08:28:02 +0100
> schrieb Stéphane Ancelot <sancelot at numalliance.com>:
>> Le 07/12/2016 à 17:16, Philippe Gerum a écrit :
>>> On 12/07/2016 03:15 PM, Stéphane Ancelot wrote:
>>>> Hi,
>>>> I noticed very bad memory allocation performance on some of my
>>>> graphic programs (standard linux applications).
>>>> If you run any classic program, you won't sea any difference, but
>>>> it has been visible in the following context :
>>>> I have an application that allocates thousends of graphic widgets,
>>>> label, input fields  at startup (a data editor) .
>>>> Using the standard kernel, the applications starts very quickly.
>>>> But once the ipipe patch is applied to kernel, this application
>>>> makes lot of seconds before appearing.
>>>> I am using a 3.18 kernel.
>>> Is there any question?
>> Euhhh ... yes,  it sounds this problem comes from ipipe
>> modifications, But I have not managed to find the reason ???
>> Is it a bug , a regression , a kernel routine where the problem is
>> amplified once the patch is applied ?
>> I remember I have not had this problem with previous kernel releases
>> (3.16.x) . I will check again with previous configurations, in order
>> to find a way of comparison.
> You can also try 4.1. And more information could be useful. Which
> version of xenomai are you using? Is your application using xenomai?
> Which architecture are you on?

I checked following things :

I have problem  with any kernel on this architecture patched with xenomai.

I tried kernel 3.16.7,3.18.20 and 4.1.18.
this happens in 32 bit or 64 bit, both SMP kernel

I made 2 traces to open with kernelshark (please advice if it is a 
problem). you have to filter task : chg_cst

this one is when the problem is happening using the computer display.


and this one is when it runs fine through a ssh -X session.

comparing both tasks  diagram , I can sea that when it does not work, 
the task is interrupted for a long time.
in other case, no interruption in it's activity diagram.


>> Regards,
>> S.Ancelot
>> _______________________________________________
>> Xenomai mailing list
>> Xenomai at xenomai.org
>> https://xenomai.org/mailman/listinfo/xenomai

More information about the Xenomai mailing list