README


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

LITMUS^RT User-Space Library: liblitmus
=======================================

  Copyright (c) 2007, 2008, 2009, 2010
  The University of North Carolina at Chapel Hill
  Department of Computer Science
  Real-Time Systems Group
  Dr. Anderson & students
  http://www.cs.unc.edu/~anderson/litmus-rt/

Released as open source under the terms of the GNU General Public License
(GPL2).

Overview
========
This library and the included tools provide the user-space interface to
LITMUS^RT. Real-time tasks should link against this library. The header file
"litmus.h" contains all necessary system calls and definitions to interact with
the kernel services provided for real-time tasks.

Tools and Programs
==================

* setsched
  Select active scheduler. Must be run as root.

* showsched
  Print the name of the currently active scheduler. Schedulers are selected at
  boot time with the "rtsched=<NAME>" kernel parameter.

* rt_launch [-p <PARTITION>] <WCET> <PERIOD> <PROGRAM> <ARGS>...
  Launch the program <PROGRAM> as a real-time task provisioned with the given
  worst-case execution time and priod. Any additional parameters are passed on
  to the real-time task.

* rtspin [-w] [-p <PARTITION>] [-c CLASS] WCET PERIOD DURATION
  rtspin -l
  A simple spin loop for emulating purely CPU-bound workloads.
  Not very realistic, but a good tool for debugging.
    -l   Start a little calibration loop.
    -w   Wait for task-system release.

* release_ts
  Release the task system. This allows for synchronous task system releases.

* measure_syscall
  A simple tool that measures the cost of a system call.

* cycles
  Display cycles per time interval.

* base_task
  Example real-time task. Can be used as a basis for the development
  of single-threaded real-time tasks.

* base_mt_task
  Example multi-threaded real-time task. Use as a basis for development.


Install
=======
The library and the included tools  must be compiled from source.
Liblitmus uses SCons as the build system. For details see:

	  http://www.scons.org/

To compile the library just execute the command 'scons' without
arguments.

x86_64->ia32 cross compilation is possible by specifying ARCH=i386 on the
command line or in the environment.