Howto implement a periodic real-time task?

Andre Puschmann andre.puschmann at
Mon Aug 10 09:26:44 CEST 2009

Hi Udo,

thanks so much for your reply and sorry for the delayed answer.
I will write a pure L4 based system trasher like you suggested.
However, as running a L4Lx next to the RT part of my system is a quite 
common use
case, I will also benchmark this part.
As I wrote in my last mail, I used hackbench [1]  (among others) to 
evaluate in legacy Linux system.
This is a quite evil tool that creates groups of tasks that communicate 
with each other via sockets.
Running this tool under L4Lx really block any other task (even with 
higher priority).
I am neither sure what exactly causes these interruption, nor how to 
eliminate them.
Any experience with these kind of tools or any other advice is highly 



Udo A. Steinberg wrote:
> On Tue, 21 Jul 2009 18:00:42 +0200 Andre Puschmann (AP) wrote:
> AP> I now want to put some load on the system as I did in native Linux with
> AP> tools like "hackbench" and "cache calibrator". Any suggestions how to
> AP> achieve this under L4? The same tools inside a L4Linux environment?
> Write some programs that continuously do IPC across task boundaries. If you
> want to trash the caches, memset contiguous regions of memory that are larger
> than the sum of all your cache sizes. The "pingpong" program should give you
> some ideas how to implement these kind of things.
> Cheers,
> 	- Udo

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