Rev 2 | Rev 14 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | RSS feed
/*
* 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>
* (see the web pages for full authors list)
*
* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
*
* http://www.sssup.it
* http://retis.sssup.it
* http://shark.sssup.it
*/
/**
------------
CVS : $Id: rm.c,v 1.1.1.1 2002-03-29 14:12:52 pj Exp $
File: $File$
Revision: $Revision: 1.1.1.1 $
Last update: $Date: 2002-03-29 14:12:52 $
------------
This file contains the scheduling module RM (Rate Monotonic)
Read rm.h for further details.
This file is equal to EDF.c except for:
. EDF changed to RM :-)
. q_timespec_insert changed to q_insert
. proc_table[p].priority is also modified when we modify lev->period[p]
**/
/*
* 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
*
*/
#include <modules/rm.h>
#include <ll/stdio.h>
#include <ll/string.h>
#include <kernel/model.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>
#include <kernel/trace.h>
/*+ Status used in the level +*/
#define RM_READY MODULE_STATUS_BASE /*+ - Ready status +*/
#define RM_DELAY MODULE_STATUS_BASE+1 /*+ - Delay status +*/
#define RM_WCET_VIOLATED MODULE_STATUS_BASE+2 /*+ when wcet is finished +*/
#define RM_WAIT MODULE_STATUS_BASE+3 /*+ to wait the deadline +*/
#define RM_IDLE MODULE_STATUS_BASE+4 /*+ to wait the deadline +*/
#define RM_ZOMBIE MODULE_STATUS_BASE+5 /*+ to wait the free time +*/
/*+ flags +*/
#define RM_FLAG_SPORADIC 1
#define RM_FLAG_NORAISEEXC 2
/*+ the level redefinition for the Rate Monotonic +*/
typedef struct {
level_des l; /*+ the standard level descriptor +*/
TIME period[MAX_PROC]; /*+ The task periods; the deadlines are
stored in the priority field +*/
int deadline_timer[MAX_PROC];
/*+ The task deadline timers +*/
int flag[MAX_PROC];
/*+ used to manage the JOB_TASK_MODEL and the
periodicity +*/
QUEUE ready; /*+ the ready queue +*/
int flags; /*+ the init flags... +*/
bandwidth_t U; /*+ the used bandwidth +*/
} RM_level_des;
static char *RM_status_to_a(WORD status)
{
if (status < MODULE_STATUS_BASE)
return status_to_a(status);
switch (status) {
case RM_READY : return "RM_Ready";
case RM_DELAY : return "RM_Delay";
case RM_WCET_VIOLATED: return "RM_Wcet_Violated";
case RM_WAIT : return "RM_Sporadic_Wait";
case RM_IDLE : return "RM_Idle";
case RM_ZOMBIE : return "RM_Zombie";
default : return "RM_Unknown";
}
}
static void RM_timer_deadline(void *par)
{
PID p = (PID) par;
RM_level_des *lev;
lev = (RM_level_des *)level_table[proc_table[p].task_level];
switch (proc_table[p].status) {
case RM_ZOMBIE:
/* we finally put the task in the ready queue */
proc_table[p].status = FREE;
q_insertfirst(p,&freedesc);
/* and free the allocated bandwidth */
lev->U -= (MAX_BANDWIDTH/lev->period[p]) * proc_table[p].wcet;
break;
case RM_IDLE:
/* tracer stuff */
trc_logevent(TRC_INTACTIVATION,&p);
/* similar to RM_task_activate */
TIMESPEC_ASSIGN(&proc_table[p].request_time,
&proc_table[p].timespec_priority);
ADDUSEC2TIMESPEC(lev->period[p], &proc_table[p].timespec_priority);
proc_table[p].status = RM_READY;
q_insert(p,&lev->ready);
lev->deadline_timer[p] = kern_event_post(&proc_table[p].timespec_priority,
RM_timer_deadline,
(void *)p);
//printk("(d%d idle priority set to %d)",p,proc_table[p].priority );
event_need_reschedule();
printk("el%d|",p);
break;
case RM_WAIT:
/* Without this, the task cannot be reactivated!!! */
proc_table[p].status = SLEEP;
break;
default:
/* else, a deadline miss occurred!!! */
kern_printf("timer_deadline:AAARRRGGGHHH!!!");
kern_raise(XDEADLINE_MISS,p);
}
}
static void RM_timer_guest_deadline(void *par)
{
PID p = (PID) par;
kern_printf("AAARRRGGGHHH!!!");
kern_raise(XDEADLINE_MISS,p);
}
/*+ this function is called when a task finish his delay +*/
static void RM_timer_delay(void *par)
{
PID p = (PID) par;
RM_level_des *lev;
lev = (RM_level_des *)level_table[proc_table[p].task_level];
proc_table[p].status = RM_READY;
q_insert(p,&lev->ready);
proc_table[p].delay_timer = NIL; /* Paranoia */
event_need_reschedule();
}
static int RM_level_accept_task_model(LEVEL l, TASK_MODEL *m)
{
if (m->pclass == HARD_PCLASS || m->pclass == (HARD_PCLASS | l)) {
HARD_TASK_MODEL *h = (HARD_TASK_MODEL *)m;
if (h->wcet && h->mit)
return 0;
}
return -1;
}
static int RM_level_accept_guest_model(LEVEL l, TASK_MODEL *m)
{
if (m->pclass == JOB_PCLASS || m->pclass == (JOB_PCLASS | l))
return 0;
else
return -1;
}
static char *onoff(int i)
{
if (i)
return "On ";
else
return "Off";
}
static void RM_level_status(LEVEL l)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
PID p = lev->ready;
kern_printf("Wcet Check : %s\n",
onoff(lev->flags & RM_ENABLE_WCET_CHECK));
kern_printf("On-line guarantee : %s\n",
onoff(lev->flags & RM_ENABLE_GUARANTEE));
kern_printf("Used Bandwidth : %u/%u\n",
lev->U, MAX_BANDWIDTH);
while (p != NIL) {
if ((proc_table[p].pclass) == JOB_PCLASS)
kern_printf("Pid: %2d (GUEST)\n", p);
else
kern_printf("Pid: %2d Name: %10s %s: %9ld Dline: %9ld.%6ld Stat: %s\n",
p,
proc_table[p].name,
lev->flag[p] & RM_FLAG_SPORADIC ? "MinITime" : "Period ",
lev->period[p],
proc_table[p].timespec_priority.tv_sec,
proc_table[p].timespec_priority.tv_nsec/1000,
RM_status_to_a(proc_table[p].status));
p = proc_table[p].next;
}
for (p=0; p<MAX_PROC; p++)
if (proc_table[p].task_level == l && proc_table[p].status != RM_READY
&& proc_table[p].status != FREE )
kern_printf("Pid: %2d Name: %10s %s: %9ld Dline: %9ld.%6ld Stat: %s\n",
p,
proc_table[p].name,
lev->flag[p] & RM_FLAG_SPORADIC ? "MinITime" : "Period ",
lev->period[p],
proc_table[p].timespec_priority.tv_sec,
proc_table[p].timespec_priority.tv_nsec/1000,
RM_status_to_a(proc_table[p].status));
}
/* The scheduler only gets the first task in the queue */
static PID RM_level_scheduler(LEVEL l)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* { // print 4 dbg the ready queue
PID p= lev->ready;
kern_printf("(s");
while (p != NIL) {
kern_printf("%d ",p);
p = proc_table[p].next;
}
kern_printf(") ");
}
*/
return (PID)lev->ready;
}
/* The on-line guarantee is enabled only if the appropriate flag is set... */
static int RM_level_guarantee(LEVEL l, bandwidth_t *freebandwidth)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
if (lev->flags & RM_FAILED_GUARANTEE) {
*freebandwidth = 0;
return 0;
}
else
if (*freebandwidth >= lev->U) {
*freebandwidth -= lev->U;
return 1;
}
else
return 0;
}
static int RM_task_create(LEVEL l, PID p, TASK_MODEL *m)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* if the RM_task_create is called, then the pclass must be a
valid pclass. */
HARD_TASK_MODEL *h = (HARD_TASK_MODEL *)m;
proc_table[p].priority = lev->period[p] = h->mit;
if (h->periodicity == APERIODIC)
lev->flag[p] = RM_FLAG_SPORADIC;
else
lev->flag[p] = 0;
lev->deadline_timer[p] = -1;
/* Enable wcet check */
if (lev->flags & RM_ENABLE_WCET_CHECK) {
proc_table[p].avail_time = h->wcet;
proc_table[p].wcet = h->wcet;
proc_table[p].control |= CONTROL_CAP;
}
/* update the bandwidth... */
if (lev->flags & RM_ENABLE_GUARANTEE) {
bandwidth_t b;
b = (MAX_BANDWIDTH / h->mit) * h->wcet;
/* really update lev->U, checking an overflow... */
if (MAX_BANDWIDTH - lev->U > b)
lev->U += b;
else
/* The task can NOT be guaranteed (U>MAX_BANDWIDTH)...
in this case, we don't raise an exception... in fact, after the
RM_task_create the task_create will call level_guarantee that return
-1... return -1 in RM_task_create isn't correct, because:
. generally, the guarantee must be done when also the resources
are registered
. returning -1 will cause the task_create to return with an errno
ETASK_CREATE instead of ENO_GUARANTEE!!!
Why I use the flag??? because if the lev->U overflows, if i.e. I set
it to MAX_BANDWIDTH, I lose the correct allocated bandwidth...
*/
lev->flags |= RM_FAILED_GUARANTEE;
}
return 0; /* OK, also if the task cannot be guaranteed... */
}
static void RM_task_detach(LEVEL l, PID p)
{
/* the RM level doesn't introduce any dinamic allocated new field.
we have only to reset the NO_GUARANTEE FIELD and decrement the allocated
bandwidth */
RM_level_des *lev = (RM_level_des *)(level_table[l]);
if (lev->flags & RM_FAILED_GUARANTEE)
lev->flags &= ~RM_FAILED_GUARANTEE;
else
lev->U -= (MAX_BANDWIDTH / lev->period[p]) * proc_table[p].wcet;
}
static int RM_task_eligible(LEVEL l, PID p)
{
return 0; /* if the task p is chosen, it is always eligible */
}
#ifdef __TEST1__
extern int testactive;
extern struct timespec s_stime[];
extern TIME s_curr[];
extern TIME s_PID[];
extern int useds;
#endif
static void RM_task_dispatch(LEVEL l, PID p, int nostop)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
// kern_printf("(disp %d)",p);
/* the task state is set EXE by the scheduler()
we extract the task from the ready queue
NB: we can't assume that p is the first task in the queue!!! */
q_extract(p, &lev->ready);
#ifdef __TEST1__
if (testactive)
{
TIMESPEC_ASSIGN(&s_stime[useds], &schedule_time);
s_curr[useds] = proc_table[p].avail_time;
s_PID[useds] = p;
useds++;
}
#endif
}
static void RM_task_epilogue(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
// kern_printf("(epil %d)",p);
/* check if the wcet is finished... */
if ((lev->flags & RM_ENABLE_WCET_CHECK) && proc_table[p].avail_time <= 0) {
/* if it is, raise a XWCET_VIOLATION exception */
kern_raise(XWCET_VIOLATION,p);
proc_table[p].status = RM_WCET_VIOLATED;
}
else {
/* the task has been preempted. it returns into the ready queue... */
q_insert(p,&lev->ready);
proc_table[p].status = RM_READY;
}
}
static void RM_task_activate(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
if (proc_table[p].status == RM_WAIT) {
kern_raise(XACTIVATION,p);
return;
}
/* Test if we are trying to activate a non sleeping task */
/* Ignore this; the task is already active */
if (proc_table[p].status != SLEEP &&
proc_table[p].status != RM_WCET_VIOLATED)
return;
/* see also RM_timer_deadline */
ll_gettime(TIME_EXACT, &proc_table[p].request_time);
TIMESPEC_ASSIGN(&proc_table[p].timespec_priority,
&proc_table[p].request_time);
ADDUSEC2TIMESPEC(lev->period[p], &proc_table[p].timespec_priority);
/* Insert task in the correct position */
proc_table[p].status = RM_READY;
q_insert(p,&lev->ready);
/* Set the deadline timer */
lev->deadline_timer[p] = kern_event_post(&proc_table[p].timespec_priority,
RM_timer_deadline,
(void *)p);
}
static void RM_task_insert(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* Similar to RM_task_activate, but we don't check in what state
the task is and we don't set the request_time*/
/* Insert task in the correct position */
proc_table[p].status = RM_READY;
q_insert(p,&lev->ready);
}
static void RM_task_extract(LEVEL l, PID p)
{
/* Extract the running task from the level
. we have already extract it from the ready queue at the dispatch time.
. the capacity event have to be removed by the generic kernel
. the wcet don't need modification...
. the state of the task is set by the calling function
. the deadline must remain...
So, we do nothing!!!
*/
}
static void RM_task_endcycle(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* the task has terminated his job before it consume the wcet. All OK! */
if (lev->flag[p] & RM_FLAG_SPORADIC)
proc_table[p].status = RM_WAIT;
else /* pclass = sporadic_pclass */
proc_table[p].status = RM_IDLE;
/* we reset the capacity counters... */
if (lev->flags & RM_ENABLE_WCET_CHECK)
proc_table[p].avail_time = proc_table[p].wcet;
/* when the deadline timer fire, it recognize the situation and set
correctly all the stuffs (like reactivation, request_time, etc... ) */
}
static void RM_task_end(LEVEL l, PID p)
{
// RM_level_des *lev = (RM_level_des *)(level_table[l]);
proc_table[p].status = RM_ZOMBIE;
/* When the deadline timer fire, it put the task descriptor in
the free queue, and free the allocated bandwidth... */
}
static void RM_task_sleep(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* the task has terminated his job before it consume the wcet. All OK! */
proc_table[p].status = RM_WAIT;
/* we reset the capacity counters... */
if (lev->flags & RM_ENABLE_WCET_CHECK)
proc_table[p].avail_time = proc_table[p].wcet;
/* when the deadline timer fire, it recognize the situation and set
correctly the task state to sleep... */
}
static void RM_task_delay(LEVEL l, PID p, TIME usdelay)
{
struct timespec wakeuptime;
// RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* equal to RM_task_endcycle */
proc_table[p].status = RM_DELAY;
/* we need to delete this event if we kill the task while it is sleeping */
ll_gettime(TIME_EXACT, &wakeuptime);
ADDUSEC2TIMESPEC(usdelay, &wakeuptime);
proc_table[p].delay_timer = kern_event_post(&wakeuptime,
RM_timer_delay,
(void *)p);
}
/* Guest Functions
These functions manages a JOB_TASK_MODEL, that is used to put
a guest task in the RM ready queue. */
static int RM_guest_create(LEVEL l, PID p, TASK_MODEL *m)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
JOB_TASK_MODEL *job = (JOB_TASK_MODEL *)m;
/* if the RM_guest_create is called, then the pclass must be a
valid pclass. */
TIMESPEC_ASSIGN(&proc_table[p].timespec_priority, &job->deadline);
lev->deadline_timer[p] = -1;
if (job->noraiseexc)
lev->flag[p] = RM_FLAG_NORAISEEXC;
else
lev->flag[p] = 0;
proc_table[p].priority = lev->period[p] = job->period;
/* there is no bandwidth guarantee at this level, it is performed
by the level that inserts guest tasks... */
return 0; /* OK, also if the task cannot be guaranteed... */
}
static void RM_guest_detach(LEVEL l, PID p)
{
/* the RM level doesn't introduce any dinamic allocated new field.
No guarantee is performed on guest tasks... so we don't have to reset
the NO_GUARANTEE FIELD */
}
static void RM_guest_dispatch(LEVEL l, PID p, int nostop)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* the task state is set to EXE by the scheduler()
we extract the task from the ready queue
NB: we can't assume that p is the first task in the queue!!! */
q_extract(p, &lev->ready);
}
static void RM_guest_epilogue(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* the task has been preempted. it returns into the ready queue... */
q_insert(p,&lev->ready);
proc_table[p].status = RM_READY;
}
static void RM_guest_activate(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* Insert task in the correct position */
q_insert(p,&lev->ready);
proc_table[p].status = RM_READY;
/* Set the deadline timer */
if (!(lev->flag[p] & RM_FLAG_NORAISEEXC))
lev->deadline_timer[p] = kern_event_post(&proc_table[p].timespec_priority,
RM_timer_guest_deadline,
(void *)p);
}
static void RM_guest_insert(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* Insert task in the correct position */
q_insert(p,&lev->ready);
proc_table[p].status = RM_READY;
}
static void RM_guest_extract(LEVEL l, PID p)
{
/* Extract the running task from the level
. we have already extract it from the ready queue at the dispatch time.
. the state of the task is set by the calling function
. the deadline must remain...
So, we do nothing!!!
*/
}
static void RM_guest_endcycle(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }
static void RM_guest_end(LEVEL l, PID p)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
//kern_printf("RM_guest_end: dline timer %d\n",lev->deadline_timer[p]);
if (proc_table[p].status == RM_READY)
{
q_extract(p, &lev->ready);
//kern_printf("(g_end rdy extr)");
}
else if (proc_table[p].status == RM_DELAY) {
event_delete(proc_table[p].delay_timer);
proc_table[p].delay_timer = NIL; /* paranoia */
}
/* we remove the deadline timer, because the slice is finished */
if (lev->deadline_timer[p] != NIL) {
// kern_printf("RM_guest_end: dline timer %d\n",lev->deadline_timer[p]);
event_delete(lev->deadline_timer[p]);
lev->deadline_timer[p] = NIL;
}
}
static void RM_guest_sleep(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }
static void RM_guest_delay(LEVEL l, PID p, TIME usdelay)
{
struct timespec wakeuptime;
// RM_level_des *lev = (RM_level_des *)(level_table[l]);
/* equal to RM_task_endcycle */
proc_table[p].status = RM_DELAY;
/* we need to delete this event if we kill the task while it is sleeping */
ll_gettime(TIME_EXACT, &wakeuptime);
ADDUSEC2TIMESPEC(usdelay, &wakeuptime);
proc_table[p].delay_timer = kern_event_post(&wakeuptime,
RM_timer_delay,
(void *)p);
}
/* Registration functions */
/*+ Registration function:
int flags the init flags ... see rm.h +*/
void RM_register_level(int flags)
{
LEVEL l; /* the level that we register */
RM_level_des *lev; /* for readableness only */
PID i; /* a counter */
printk("RM_register_level\n");
/* request an entry in the level_table */
l = level_alloc_descriptor();
/* alloc the space needed for the RM_level_des */
lev = (RM_level_des *)kern_alloc(sizeof(RM_level_des));
printk(" lev=%d\n",(int)lev);
/* update the level_table with the new entry */
level_table[l] = (level_des *)lev;
/* fill the standard descriptor */
strncpy(lev->l.level_name, RM_LEVELNAME, MAX_LEVELNAME);
lev->l.level_code = RM_LEVEL_CODE;
lev->l.level_version = RM_LEVEL_VERSION;
lev->l.level_accept_task_model = RM_level_accept_task_model;
lev->l.level_accept_guest_model = RM_level_accept_guest_model;
lev->l.level_status = RM_level_status;
lev->l.level_scheduler = RM_level_scheduler;
if (flags & RM_ENABLE_GUARANTEE)
lev->l.level_guarantee = RM_level_guarantee;
else
lev->l.level_guarantee = NULL;
lev->l.task_create = RM_task_create;
lev->l.task_detach = RM_task_detach;
lev->l.task_eligible = RM_task_eligible;
lev->l.task_dispatch = RM_task_dispatch;
lev->l.task_epilogue = RM_task_epilogue;
lev->l.task_activate = RM_task_activate;
lev->l.task_insert = RM_task_insert;
lev->l.task_extract = RM_task_extract;
lev->l.task_endcycle = RM_task_endcycle;
lev->l.task_end = RM_task_end;
lev->l.task_sleep = RM_task_sleep;
lev->l.task_delay = RM_task_delay;
lev->l.guest_create = RM_guest_create;
lev->l.guest_detach = RM_guest_detach;
lev->l.guest_dispatch = RM_guest_dispatch;
lev->l.guest_epilogue = RM_guest_epilogue;
lev->l.guest_activate = RM_guest_activate;
lev->l.guest_insert = RM_guest_insert;
lev->l.guest_extract = RM_guest_extract;
lev->l.guest_endcycle = RM_guest_endcycle;
lev->l.guest_end = RM_guest_end;
lev->l.guest_sleep = RM_guest_sleep;
lev->l.guest_delay = RM_guest_delay;
/* fill the RM descriptor part */
for(i=0; i<MAX_PROC; i++) {
lev->period[i] = 0;
lev->deadline_timer[i] = -1;
lev->flag[i] = 0;
}
lev->ready = NIL;
lev->flags = flags & 0x07;
lev->U = 0;
}
bandwidth_t RM_usedbandwidth(LEVEL l)
{
RM_level_des *lev = (RM_level_des *)(level_table[l]);
if (lev->l.level_code == RM_LEVEL_CODE &&
lev->l.level_version == RM_LEVEL_VERSION)
return lev->U;
else
return 0;
}