Subversion Repositories shark

/*

 * 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: edf.c,v 1.12 2004-02-10 17:50:04 giacomo Exp $

 File:        $File$

 Revision:    $Revision: 1.12 $

 Last update: $Date: 2004-02-10 17:50:04 $

 ------------

 This file contains the scheduling module EDF (Earliest Deadline First)

 Read edf.h for further details.

**/

/*

 * Copyright (C) 2000,2002 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/edf.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>

//#define EDF_DEBUG

#define edf_printf kern_printf

/*+ Status used in the level +*/

#define EDF_READY         MODULE_STATUS_BASE    /*+ - Ready status        +*/

#define EDF_WCET_VIOLATED MODULE_STATUS_BASE+2  /*+ when wcet is finished +*/

#define EDF_WAIT          MODULE_STATUS_BASE+3  /*+ to wait the deadline  +*/

#define EDF_IDLE          MODULE_STATUS_BASE+4  /*+ to wait the deadline  +*/

#define EDF_ZOMBIE        MODULE_STATUS_BASE+5  /*+ to wait the free time +*/

/*+ flags +*/

#define EDF_FLAG_SPORADIC    1

#define EDF_FLAG_NORAISEEXC  2

#define EDF_FLAG_SLEEP       4

/*+ the level redefinition for the Earliest Deadline First level +*/

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                            +*/

  IQUEUE ready;     /*+ the ready queue                        +*/

  int flags;       /*+ the init flags...                      +*/

  bandwidth_t U;   /*+ the used bandwidth                     +*/

} EDF_level_des;

static void EDF_timer_deadline(void *par)

{

  PID p = (PID) par;

  EDF_level_des *lev;

  struct timespec *temp;

  lev = (EDF_level_des *)level_table[proc_table[p].task_level];

  #ifdef EDF_DEBUG

    edf_printf("(EDF:Dl TIMER:%d)",p);

  #endif

  switch (proc_table[p].status) {

    case EDF_ZOMBIE:

      /* we finally put the task in the ready queue */

      proc_table[p].status = FREE;

      iq_insertfirst(p,&freedesc);

      /* and free the allocated bandwidth */

      lev->U -= (MAX_BANDWIDTH/lev->period[p]) * proc_table[p].wcet;

      break;

    case EDF_IDLE:

      /* tracer stuff */

      TRACER_LOGEVENT(FTrace_EVT_task_timer,3,proc_table[p].context,proc_table[p].task_level);

      /* similar to EDF_task_activate */

      temp = iq_query_timespec(p,&lev->ready);

      ADDUSEC2TIMESPEC(lev->period[p], temp);

      proc_table[p].status = EDF_READY;

      iq_timespec_insert(p,&lev->ready);

      lev->deadline_timer[p] = kern_event_post(temp,

                                               EDF_timer_deadline,

                                               (void *)p);

      event_need_reschedule();

      break;

    case EDF_WAIT:

      /* Without this, the task cannot be reactivated!!! */

      proc_table[p].status = SLEEP;

      /* Reset the EDF_FLAG_SLEEP */

      lev->flag[p] &= ~EDF_FLAG_SLEEP;

      break;

    default:

      /* else, a deadline miss occurred!!! */

      TRACER_LOGEVENT(FTrace_EVT_task_deadline_miss,1,proc_table[p].context,0);

      kern_raise(XDEADLINE_MISS,p);

  }

}

static void EDF_timer_guest_deadline(void *par)

{

  PID p = (PID) par;

  #ifdef EDF_DEBUG

    edf_printf("(EDF:AAARRRGGGHHH!!!)");

  #endif

  TRACER_LOGEVENT(FTrace_EVT_task_deadline_miss,1,proc_table[p].context,0);

  kern_raise(XDEADLINE_MISS,p);

}

/* The scheduler only gets the first task in the queue */

static PID EDF_public_scheduler(LEVEL l)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  return iq_query_first(&lev->ready);

}

/* The on-line guarantee is enabled only if the appropriate flag is set... */

static int EDF_public_guarantee(LEVEL l, bandwidth_t *freebandwidth)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  if (*freebandwidth >= lev->U) {

    *freebandwidth -= lev->U;

    return 1;

  }

  else

    return 0;

}

static int EDF_public_create(LEVEL l, PID p, TASK_MODEL *m)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  HARD_TASK_MODEL *h;

  if (m->pclass != HARD_PCLASS) return -1;

  if (m->level != 0 && m->level != l) return -1;

  h = (HARD_TASK_MODEL *)m;

  if (!h->wcet || !h->mit) return -1;

  /* check the free bandwidth... */

  if (lev->flags & EDF_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

      return -1;

  }

  /* now we know that m is a valid model */

  #ifdef EDF_DEBUG

    edf_printf("(EDF:PubCrt:%d)", p);

  #endif

  lev->period[p] = h->mit;

  lev->flag[p] = 0;

  if (h->periodicity == APERIODIC)

    lev->flag[p] |= EDF_FLAG_SPORADIC;

  lev->deadline_timer[p] = -1;

  /* Enable wcet check */

  if (lev->flags & EDF_ENABLE_WCET_CHECK) {

    proc_table[p].avail_time = h->wcet;

    proc_table[p].wcet       = h->wcet;

    proc_table[p].control |= CONTROL_CAP;

  }

  return 0; /* OK, also if the task cannot be guaranteed... */

}

static void EDF_public_detach(LEVEL l, PID p)

{

  /* the EDF level doesn't introduce any dinamic allocated new field.

     we have only to decrement the allocated bandwidth */

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  #ifdef EDF_DEBUG

    edf_printf("(EDF:PubDet:%d)", p);

  #endif

  if (lev->flags & EDF_ENABLE_GUARANTEE) {

    lev->U -= (MAX_BANDWIDTH / lev->period[p]) * proc_table[p].wcet;

  }

}

static void EDF_public_dispatch(LEVEL l, PID p, int nostop)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  #ifdef EDF_DEBUG

    edf_printf("(EDF:PubDsp:%d)",p);

  #endif

  /* 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!!! */

  iq_extract(p, &lev->ready);

}

static void EDF_public_epilogue(LEVEL l, PID p)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  #ifdef EDF_DEBUG

    edf_printf("(EDF:PubEpi:%d)",p);

  #endif

  /* check if the wcet is finished... */

  if ((lev->flags & EDF_ENABLE_WCET_CHECK) && proc_table[p].avail_time <= 0) {

    /* if it is, raise a XWCET_VIOLATION exception */

    TRACER_LOGEVENT(FTrace_EVT_task_wcet_violation,1,proc_table[p].context,0);

    kern_raise(XWCET_VIOLATION,p);

    proc_table[p].status = EDF_WCET_VIOLATED;

  }

  else {

    /* the task has been preempted. it returns into the ready queue... */

    iq_timespec_insert(p,&lev->ready);

    proc_table[p].status = EDF_READY;

  }

}

static void EDF_public_activate(LEVEL l, PID p)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  struct timespec *temp;

  #ifdef EDF_DEBUG

    edf_printf("(EDF:PubAct:%d)", p);

  #endif

  if (lev->flag[p] & EDF_FLAG_SLEEP) {

    lev->flag[p] &= ~EDF_FLAG_SLEEP;

    if (!(lev->flag[p] & EDF_FLAG_SPORADIC))

      proc_table[p].status = EDF_IDLE;

    return;

  }

  if (proc_table[p].status == EDF_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 != EDF_WCET_VIOLATED)

    return;

  /* see also EDF_timer_deadline */

  temp = iq_query_timespec(p, &lev->ready);

  kern_gettime(temp);

  ADDUSEC2TIMESPEC(lev->period[p], temp);

  /* Insert task in the correct position */

  proc_table[p].status = EDF_READY;

  iq_timespec_insert(p,&lev->ready);

  /* Set the deadline timer */

  lev->deadline_timer[p] = kern_event_post(temp,

                                           EDF_timer_deadline,

                                           (void *)p);

}

static void EDF_public_unblock(LEVEL l, PID p)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  /* Similar to EDF_task_activate,

     but we don't check in what state the task is */

  /* Insert task in the coEDFect position */

  proc_table[p].status = EDF_READY;

  iq_timespec_insert(p,&lev->ready);

}

static void EDF_public_block(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 int EDF_public_message(LEVEL l, PID p, void *m)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  /* task_message evaluation */

  switch((long)(m)) {

    /* task_endcycle */

    case (long)(NULL):

      #ifdef EDF_DEBUG

        edf_printf("(EDF:EndCyc:%d)",p);

      #endif

      /* the task has terminated his job before it consume the wcet. All OK! */

      if (!(lev->flag[p] & EDF_FLAG_SPORADIC) &&

          !(lev->flag[p] & EDF_FLAG_SLEEP))

        proc_table[p].status = EDF_IDLE;

      else

        proc_table[p].status = EDF_WAIT;

      /* we reset the capacity counters... */

      if (lev->flags & EDF_ENABLE_WCET_CHECK)

        proc_table[p].avail_time = proc_table[p].wcet;

      jet_update_endcycle(); /* Update the Jet data... */

      TRACER_LOGEVENT(FTrace_EVT_task_end_cycle,3,proc_table[p].context,l);

      break;

    /* task_disable */

    case 1:

      #ifdef EDF_DEBUG

        edf_printf("(EDF:Dis:%d)",p);

      #endif

      /* Set the EDF_FLAG_SLEEP, in the next endcycle the task will

         be set in EDF_WAIT */

      lev->flag[p] |= EDF_FLAG_SLEEP;

      /* If the task is EDF_IDLE, set to EDF_WAIT now */

      if (proc_table[p].status == EDF_IDLE)

        proc_table[p].status = EDF_WAIT;

      TRACER_LOGEVENT(FTrace_EVT_task_disable,3,proc_table[p].context,l);

      break;

  }

  return 0;

}

static void EDF_public_end(LEVEL l, PID p)

{

  proc_table[p].status = EDF_ZOMBIE;

  /* When the deadline timer fire, it put the task descriptor in

     the free queue, and free the allocated bandwidth... */

}

static void EDF_private_insert(LEVEL l, PID p, TASK_MODEL *m)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  JOB_TASK_MODEL *job;

  if (m->pclass != JOB_PCLASS || (m->level != 0 && m->level != l) ) {

    kern_raise(XINVALID_TASK, p);

    return;

  }

  job = (JOB_TASK_MODEL *)m;

  /* Insert task in the correct position */

  *iq_query_timespec(p, &lev->ready) = job->deadline;

  iq_timespec_insert(p,&lev->ready);

  proc_table[p].status = EDF_READY;

  lev->deadline_timer[p] = -1;

  lev->period[p] = job->period;

  /* Set the deadline timer */

  if (job->noraiseexc)

    lev->flag[p] = EDF_FLAG_NORAISEEXC;

  else {

    lev->flag[p] = 0;

    lev->deadline_timer[p] = kern_event_post(iq_query_timespec(p, &lev->ready),

                                             EDF_timer_guest_deadline,

                                             (void *)p);

  }

}

static void EDF_private_dispatch(LEVEL l, PID p, int nostop)

{

  EDF_level_des *lev = (EDF_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!!! */

  iq_extract(p, &lev->ready);

}

static void EDF_private_epilogue(LEVEL l, PID p)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  /* the task has been preempted. it returns into the ready queue... */

  iq_timespec_insert(p,&lev->ready);

  proc_table[p].status = EDF_READY;

}

static void EDF_private_extract(LEVEL l, PID p)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  if (proc_table[p].status == EDF_READY)

    iq_extract(p, &lev->ready);

  /* we remove the deadline timer, because the slice is finished */

  if (lev->deadline_timer[p] != NIL) {

    kern_event_delete(lev->deadline_timer[p]);

    lev->deadline_timer[p] = NIL;

  }

}

/* Registration functions */

/*+ Registration function:

    int flags                 the init flags ... see edf.h +*/

LEVEL EDF_register_level(int flags)

{

  LEVEL l;            /* the level that we register */

  EDF_level_des *lev;  /* for readableness only */

  PID i;              /* a counter */

  printk("EDF_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor(sizeof(EDF_level_des));

  lev = (EDF_level_des *)level_table[l];

  /* fill the standard descriptor */

  lev->l.private_insert   = EDF_private_insert;

  lev->l.private_extract  = EDF_private_extract;

  lev->l.private_dispatch = EDF_private_dispatch;

  lev->l.private_epilogue = EDF_private_epilogue;

  lev->l.public_scheduler = EDF_public_scheduler;

  if (flags & EDF_ENABLE_GUARANTEE)

    lev->l.public_guarantee = EDF_public_guarantee;

  else

    lev->l.public_guarantee = NULL;

  lev->l.public_create    = EDF_public_create;

  lev->l.public_detach    = EDF_public_detach;

  lev->l.public_end       = EDF_public_end;

  lev->l.public_dispatch  = EDF_public_dispatch;

  lev->l.public_epilogue  = EDF_public_epilogue;

  lev->l.public_activate  = EDF_public_activate;

  lev->l.public_unblock   = EDF_public_unblock;

  lev->l.public_block     = EDF_public_block;

  lev->l.public_message   = EDF_public_message;

  /* fill the EDF descriptor part */

  for(i=0; i<MAX_PROC; i++) {

    lev->period[i]         = 0;

    lev->deadline_timer[i] = -1;

    lev->flag[i]          = 0;

  }

  iq_init(&lev->ready, &freedesc, 0);

  lev->flags = flags;

  lev->U     = 0;

  return l;

}

bandwidth_t EDF_usedbandwidth(LEVEL l)

{

  EDF_level_des *lev = (EDF_level_des *)(level_table[l]);

  return lev->U;

}