The system call about Periodic task

Jungwoo Yang yjwoo14 at
Wed Apr 28 03:55:48 CEST 2010

 I tried to use time periodic task designed by Udo. However, the process using the system call does not enter into periodic mode.
So I tried to analyze kernel source code. During examining kernel source code, I found the wired point.

line 584 in syscalls.cpp
	regs->old_param (dst->begin_periodic (regs->time(), 0));

I think that the parameter should be "Periodic" instead of 0.
Because the point is for entering periodic mode and 0 means that conventional mode, I think 0 should be changed into "Periodic".
After modification of this, A task using the system call enters periodic mode ( I check this by using JDB debugger ).

I cannot ensure that this is correct code, but It seems to be working.
So, if anyone who want to use periodic task and think that it is not working, just try to modify this code.

Thank you for Adam Lackorzynski and Cheng Cuanghui

Thank you.

Jungwoo Yang.

More information about the l4-hackers mailing list