| 0,0 → 1,137 |
|---|
| /* |
| * Project: S.Ha.R.K. |
| * |
| * Coordinators: |
| * Giorgio Buttazzo <giorgio@sssup.it> |
| * Paolo Gai <pj@gandalf.sssup.it> |
| * |
| * Authors : |
| * Paolo Gai <pj@gandalf.sssup.it> |
| * Massimiliano Giorgi <massy@gandalf.sssup.it> |
| * Luca Abeni <luca@gandalf.sssup.it> |
| * Giacomo Guidi <giacomo@gandalf.sssup.it> |
| * |
| * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy) |
| * |
| * http://www.sssup.it |
| * http://retis.sssup.it |
| * http://shark.sssup.it |
| */ |
| |
| /* |
| |
| This file contains the aperiodic server CBS (Total Bandwidth Server) |
| with hard reservation and met/period update |
| |
| Title: |
| CBS (Constant Bandwidth Server) |
| |
| Task Models Accepted: |
| SOFT_TASK_MODEL - Soft Tasks |
| wcet field is ignored |
| met field must be != 0 |
| period field must be != 0 |
| periodicity field can be either PERIODIC or APERIODIC |
| arrivals field can be either SAVE or SKIP |
| |
| Description: |
| This module schedule his tasks following the CBS scheme. |
| (see Luca Abeni and Giorgio Buttazzo, |
| "Integrating Multimedia Applications in Hard Real-Time Systems" |
| Proceedings of the IEEE Real-Time Systems Symposium, Madrid, Spain, |
| December 1998) |
| |
| The tasks are inserted in an EDF level (or similar) with a JOB_TASK_MODEL, |
| and the CBS level expects that the task is scheduled with the absolute |
| deadline passed in the model. |
| |
| The task guarantee is based on the factor utilization approach. |
| |
| Exceptions raised: |
| XUNVALID_GUEST |
| This level doesn't support guests. When a guest operation |
| is called, the exception is raised. |
| |
| These exceptions are pclass-dependent... |
| XDEADLINE_MISS |
| If a task miss his deadline, the exception is raised. |
| Normally, a CBS task can't cause the raise of such exception because |
| if it really use more time than declared the deadline is postponed. |
| |
| Restrictions & special features: |
| - This level doesn't manage the main task. |
| - At init time we have to specify: |
| . guarantee check |
| (when all task are created the system will check that the task_set |
| will not use more than the available bandwidth) |
| - A function to return the used bandwidth of the level is provided. |
| - A function to return the pending activations of the task. |
| |
| **/ |
| |
| /* |
| * Copyright (C) 2000 Paolo Gai |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| |
| |
| #ifndef __HCBS_H__ |
| #define __HCBS_H__ |
| |
| #include <ll/ll.h> |
| #include <kernel/config.h> |
| #include <sys/types.h> |
| #include <kernel/types.h> |
| #include "ll/sys/cdefs.h" |
| |
| __BEGIN_DECLS |
| |
| /*+ flags... +*/ |
| #define HCBS_DISABLE_ALL 0 /*+ Task Guarantee enabled +*/ |
| #define HCBS_ENABLE_GUARANTEE 1 /*+ Task Guarantee enabled +*/ |
| #define HCBS_ENABLE_ALL 1 |
| |
| #define HCBS_SET_PERIOD 0 |
| #define HCBS_GET_PERIOD 1 |
| #define HCBS_SET_MET 2 |
| #define HCBS_GET_MET 3 |
| |
| typedef struct { |
| |
| int command; |
| TIME param; |
| |
| } HCBS_command_message; |
| |
| /*+ Registration function: |
| int flags Options to be used in this level instance... |
| LEVEL master the level that must be used as master level for the |
| CBS tasks |
| |
| returns the level number at which the module has been registered. |
| +*/ |
| LEVEL HCBS_register_level(int flags, LEVEL master); |
| |
| /*+ Returns the used bandwidth of a level +*/ |
| bandwidth_t HCBS_usedbandwidth(LEVEL l); |
| |
| /*+ Returns the number of pending activations of a task. |
| No control is done if the task is not a CBS task! +*/ |
| int HCBS_get_nact(LEVEL l, PID p); |
| |
| __END_DECLS |
| #endif |