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/*
* 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: ds.c,v 1.5 2003-12-10 16:54:59 giacomo Exp $
File: $File$
Revision: $Revision: 1.5 $
Last update: $Date: 2003-12-10 16:54:59 $
------------
This file contains the aperiodic server DS (Deferrable Server)
This module is directly derived from the Polling server one.
All the notes writed for the PS are valid for the DS.
The difference between DS and PS is that when there are not task to
schedule the capacity is not reset to 0...
**/
/*
* 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/ds.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 <tracer.h>
/*+ Status used in the level +*/
#define DS_WAIT APER_STATUS_BASE /*+ waiting the service +*/
/*+ the level redefinition for the Total Bandwidth Server level +*/
typedef struct {
level_des l; /*+ the standard level descriptor +*/
/* The wcet are stored in the task descriptor's priority
field, so no other fields are needed */
int nact[MAX_PROC]; /*+ number of pending activations +*/
struct timespec lastdline; /*+ the last deadline assigned to
a DS task +*/
int Cs; /*+ server capacity +*/
int availCs; /*+ server avail time +*/
IQUEUE wait; /*+ the wait queue of the DS +*/
PID activated; /*+ the task inserted in another queue +*/
int flags; /*+ the init flags... +*/
bandwidth_t U; /*+ the used bandwidth by the server +*/
int period;
LEVEL scheduling_level;
} DS_level_des;
/* This static function activates the task pointed by lev->activated) */
static __inline__ void DS_activation(DS_level_des *lev)
{
PID p; /* for readableness */
JOB_TASK_MODEL j; /* the guest model */
LEVEL m; /* the master level... only for readableness*/
p = lev->activated;
m = lev->scheduling_level;
job_task_default_model(j,lev->lastdline);
job_task_def_period(j,lev->period);
level_table[m]->private_insert(m,p,(TASK_MODEL *)&j);
// kern_printf("(%d %d)",lev->lastdline.tv_sec,lev->lastdline.tv_nsec);
}
static void DS_deadline_timer(void *a)
{
DS_level_des *lev = (DS_level_des *)(level_table[(LEVEL)a]);
ADDUSEC2TIMESPEC(lev->period, &lev->lastdline);
// kern_printf("(%d:%d %d)",lev->lastdline.tv_sec,lev->lastdline.tv_nsec, lev->period);
if (lev->availCs >= 0)
lev->availCs = lev->Cs;
else
lev->availCs += lev->Cs;
/* availCs may be <0 because a task executed via a shadow fo many time
lev->activated == NIL only if the prec task was finished and there
was not any other task to be put in the ready queue
... we are now activating the next task */
if (lev->availCs > 0 && lev->activated == NIL) {
if (iq_query_first(&lev->wait) != NIL) {
lev->activated = iq_getfirst(&lev->wait);
DS_activation(lev);
event_need_reschedule();
}
}
kern_event_post(&lev->lastdline, DS_deadline_timer, a);
// kern_printf("!");
}
static PID DS_public_schedulerbackground(LEVEL l)
{
/* the DS catch the background time to exec aperiodic activities */
DS_level_des *lev = (DS_level_des *)(level_table[l]);
lev->flags |= DS_BACKGROUND;
if (lev->flags & DS_BACKGROUND_BLOCK)
return NIL;
else
return iq_query_first(&lev->wait);
}
/* The on-line guarantee is enabled only if the appropriate flag is set... */
static int DS_public_guaranteeEDF(LEVEL l, bandwidth_t *freebandwidth)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
if (*freebandwidth >= lev->U) {
*freebandwidth -= lev->U;
return 1;
}
else
return 0;
}
static int DS_public_guaranteeRM(LEVEL l, bandwidth_t *freebandwidth)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
if (*freebandwidth > lev->U + RM_MINFREEBANDWIDTH) {
*freebandwidth -= lev->U;
return 1;
}
else
return 0;
}
static int DS_public_create(LEVEL l, PID p, TASK_MODEL *m)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
SOFT_TASK_MODEL *s;
if (m->pclass != SOFT_PCLASS) return -1;
if (m->level != 0 && m->level != l) return -1;
s = (SOFT_TASK_MODEL *)m;
if (s->periodicity != APERIODIC) return -1;
s = (SOFT_TASK_MODEL *)m;
if (s->arrivals == SAVE_ARRIVALS)
lev->nact[p] = 0;
else
lev->nact[p] = -1;
return 0; /* OK, also if the task cannot be guaranteed... */
}
static void DS_public_dispatch(LEVEL l, PID p, int nostop)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
struct timespec ty;
// if (nostop) kern_printf("NOSTOP!!!!!!!!!!!!");
/* there is at least one task ready inserted in an EDF or similar
level note that we can't check the status because the scheduler set it
to exe before calling task_dispatch. we have to check
lev->activated != p instead */
if (lev->activated != p) {
iq_extract(p, &lev->wait);
//kern_printf("#%d#",p);
}
else {
//if (nostop) kern_printf("(gd status=%d)",proc_table[p].status);
level_table[ lev->scheduling_level ]->
private_dispatch(lev->scheduling_level,p,nostop);
}
/* set the capacity timer */
if (!nostop) {
TIMESPEC_ASSIGN(&ty, &schedule_time);
ADDUSEC2TIMESPEC(lev->availCs,&ty);
cap_timer = kern_event_post(&ty, capacity_timer, NULL);
}
// kern_printf("(disp %d %d)",ty.tv_sec, ty.tv_nsec);
}
static void DS_public_epilogue(LEVEL l, PID p)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
struct timespec ty;
TIME tx;
/* update the server capacity */
if (lev->flags & DS_BACKGROUND)
lev->flags &= ~DS_BACKGROUND;
else {
SUBTIMESPEC(&schedule_time, &cap_lasttime, &ty);
tx = TIMESPEC2USEC(&ty);
lev->availCs -= tx;
}
// kern_printf("(epil %d %d)",lev->availCs, proc_table[p].avail_time);
/* check if the server capacity is finished... */
if (lev->availCs < 0) {
// kern_printf("(epil Cs%d %d:%d act%d p%d)",
// lev->availCs,proc_table[p].timespec_priority.tv_sec,
// proc_table[p].timespec_priority.tv_nsec,
// lev->activated,p);
/* the server slice has finished... do the task_end!!!
a first version of the module used the task_endcycle, but it was
not conceptually correct because the task didn't stop because it
finished all the work but because the server didn't have budget!
So, if the task_endcycle is called, the task remain into the
master level, and we can't wake him up if, for example, another
task point the shadow to it!!!*/
if (lev->activated == p)
level_table[ lev->scheduling_level ]->
private_extract(lev->scheduling_level,p);
iq_insertfirst(p, &lev->wait);
proc_table[p].status = DS_WAIT;
lev->activated = NIL;
}
else
/* the task has been preempted. it returns into the ready queue or to the
wait queue by calling the guest_epilogue... */
if (lev->activated == p) {//kern_printf("Û1");
level_table[ lev->scheduling_level ]->
private_epilogue(lev->scheduling_level,p);
} else { //kern_printf("Û2");
iq_insertfirst(p, &lev->wait);
proc_table[p].status = DS_WAIT;
}
}
static void DS_public_activate(LEVEL l, PID p)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
if (lev->activated == p || proc_table[p].status == DS_WAIT) {
if (lev->nact[p] != -1)
lev->nact[p]++;
}
else if (proc_table[p].status == SLEEP) {
if (lev->activated == NIL && lev->availCs > 0) {
lev->activated = p;
DS_activation(lev);
}
else {
iq_insertlast(p, &lev->wait);
proc_table[p].status = DS_WAIT;
}
}
else
{ kern_printf("DS_REJ%d %d %d %d ",p, proc_table[p].status, lev->activated, lev->wait.first);
return; }
}
static void DS_public_unblock(LEVEL l, PID p)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
lev->flags &= ~DS_BACKGROUND_BLOCK;
lev->activated = -1;
/* when we reinsert the task into the system, the server capacity
is always 0 because nobody executes with the DS before... */
iq_insertfirst(p, &lev->wait);
proc_table[p].status = DS_WAIT;
}
static void DS_public_block(LEVEL l, PID p)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
/* update the server capacity */
lev->availCs = 0;
lev->flags |= DS_BACKGROUND_BLOCK;
if (lev->activated == p)
level_table[ lev->scheduling_level ]->
private_extract(lev->scheduling_level,p);
}
static int DS_public_message(LEVEL l, PID p, void *m)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
struct timespec ty;
TIME tx;
/* update the server capacity */
if (lev->flags & DS_BACKGROUND)
lev->flags &= ~DS_BACKGROUND;
else {
SUBTIMESPEC(&schedule_time, &cap_lasttime, &ty);
tx = TIMESPEC2USEC(&ty);
lev->availCs -= tx;
}
if (lev->activated == p)
level_table[ lev->scheduling_level ]->
private_extract(lev->scheduling_level,p);
else
iq_extract(p, &lev->wait);
if (lev->nact[p] > 0)
{
lev->nact[p]--;
iq_insertlast(p, &lev->wait);
proc_table[p].status = DS_WAIT;
}
else
proc_table[p].status = SLEEP;
lev->activated = iq_getfirst(&lev->wait);
if (lev->activated != NIL)
DS_activation(lev);
jet_update_endcycle(); /* Update the Jet data... */
TRACER_LOGEVENT(FTrace_EVT_task_end_cycle,3,p,l);
return 0;
}
static void DS_public_end(LEVEL l, PID p)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
struct timespec ty;
TIME tx;
/* update the server capacity */
if (lev->flags & DS_BACKGROUND)
lev->flags &= ~DS_BACKGROUND;
else {
SUBTIMESPEC(&schedule_time, &cap_lasttime, &ty);
tx = TIMESPEC2USEC(&ty);
lev->availCs -= tx;
}
if (lev->activated == p)
level_table[ lev->scheduling_level ]->
private_extract(lev->scheduling_level,p);
proc_table[p].status = FREE;
iq_insertfirst(p,&freedesc);
lev->activated = iq_getfirst(&lev->wait);
if (lev->activated != NIL)
DS_activation(lev);
}
/* Registration functions */
/*+ This init function install the DS deadline timer
+*/
static void DS_dline_install(void *l)
{
DS_level_des *lev = (DS_level_des *)(level_table[(LEVEL)l]);
kern_gettime(&lev->lastdline);
ADDUSEC2TIMESPEC(lev->period, &lev->lastdline);
kern_event_post(&lev->lastdline, DS_deadline_timer, l);
}
/*+ Registration function:
int flags the init flags ... see DS.h +*/
LEVEL DS_register_level(int flags, LEVEL master, int Cs, int per)
{
LEVEL l; /* the level that we register */
DS_level_des *lev; /* for readableness only */
PID i; /* a counter */
printk("DS_register_level\n");
/* request an entry in the level_table */
l = level_alloc_descriptor(sizeof(DS_level_des));
lev = (DS_level_des *)level_table[l];
printk(" lev=%d\n",(int)lev);
/* fill the standard descriptor */
if (flags & DS_ENABLE_BACKGROUND)
lev->l.public_scheduler = DS_public_schedulerbackground;
if (flags & DS_ENABLE_GUARANTEE_EDF)
lev->l.public_guarantee = DS_public_guaranteeEDF;
else if (flags & DS_ENABLE_GUARANTEE_RM)
lev->l.public_guarantee = DS_public_guaranteeRM;
else
lev->l.public_guarantee = NULL;
lev->l.public_create = DS_public_create;
lev->l.public_end = DS_public_end;
lev->l.public_dispatch = DS_public_dispatch;
lev->l.public_epilogue = DS_public_epilogue;
lev->l.public_activate = DS_public_activate;
lev->l.public_unblock = DS_public_unblock;
lev->l.public_block = DS_public_block;
lev->l.public_message = DS_public_message;
/* fill the DS descriptor part */
for (i=0; i<MAX_PROC; i++)
lev->nact[i] = -1;
lev->Cs = Cs;
lev->availCs = 0;
lev->period = per;
iq_init(&lev->wait, &freedesc, 0);
lev->activated = NIL;
lev->U = (MAX_BANDWIDTH / per) * Cs;
lev->scheduling_level = master;
lev->flags = flags & 0x07;
sys_atrunlevel(DS_dline_install,(void *) l, RUNLEVEL_INIT);
return l;
}
bandwidth_t DS_usedbandwidth(LEVEL l)
{
DS_level_des *lev = (DS_level_des *)(level_table[l]);
return lev->U;
}