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/*

 * Project: S.Ha.R.K.

 *

 * Coordinators:

 *   Giorgio Buttazzo    <giorgio@sssup.it>

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *

 * Authors:

 *      Giacomo Guidi    <giacomo@gandalf.sssup.it>

 *      Mauro Marinoni

 *      Anton Cervin

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/*

 * 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 <kernel/model.h>

#include <kernel/descr.h>

#include <kernel/var.h>

#include <kernel/func.h>

#include <stdlib.h>

#include <modules/elastic.h>

#include <tracer.h>

/* Task flags */

#define ELASTIC_PRESENT       1

#define ELASTIC_JOB_PRESENT   2  

/* Task statuses */

#define ELASTIC_IDLE          APER_STATUS_BASE

#define ELASTIC_DEBUG

#ifdef ELASTIC_DEBUG

char *pnow() {

  static char buf[40];

  struct timespec t;

  kern_gettime(&t);

  sprintf(buf, "%ld.%06ld", t.tv_sec, t.tv_nsec/1000);

  return buf;

}

char *ptime1(struct timespec *t) {

  static char buf[40];

  sprintf(buf, "%ld.%06ld", t->tv_sec, t->tv_nsec/1000);

  return buf;

}

char *ptime2(struct timespec *t) {

  static char buf[40];

  sprintf(buf, "%ld.%06ld", t->tv_sec, t->tv_nsec/1000);

  return buf;

}

#endif

typedef struct {

  /* Task parameters (set/changed by the user) */

  TIME Tmin;   /* The nominal (minimum) period */

  TIME Tmax;   /* The maximum tolerable period */

  TIME C;      /* The declared worst-case execution time */

  int  E;      /* The elasticity coefficient */

  int  beta;   /* PERIOD_SCALING or WCET_SCALING */

  /* Task variables (changed by the module) */

  struct timespec release;    /* The current activation time */

  struct timespec dline;      /* The current absolute deadline */

  int dltimer;                /* Deadline timer handle */

  ext_bandwidth_t Umax;       /* The maximum utilization, Umax = C/Tmin  */

  ext_bandwidth_t Umin;       /* The minimum utilization, Umin = C/Tmax  */

  ext_bandwidth_t U;          /* New assigned utilization             */

  ext_bandwidth_t oldU;       /* Old utilization                      */

  TIME T;                     /* The current period, T = C/U          */

  int  flags;

} ELASTIC_task_descr;

typedef struct {

  level_des l;     /*+ the standard level descriptor          +*/

  ext_bandwidth_t U;   /*+ the bandwidth reserved for elastic tasks  +*/

  ELASTIC_task_descr elist[MAX_PROC];

  LEVEL scheduling_level;

  LEVEL current_level;

  int flags;

} ELASTIC_level_des;

static void ELASTIC_activation(ELASTIC_level_des *lev, PID p,

                               struct timespec *acttime)

{

  JOB_TASK_MODEL job;

  ELASTIC_task_descr *et = &lev->elist[p];

  /* Assign release time */

  et->release = *acttime;

  /* Assign absolute deadline */

  et->dline = *acttime;

  ADDUSEC2TIMESPEC(et->T, &et->dline);

#ifdef ELASTIC_DEBUG

  cprintf("At %s: activating %s; rel=%s; dl=%s\n", pnow(), proc_table[p].name,

          ptime1(&et->release), ptime2(&et->dline));

#endif  

  proc_table[p].avail_time = et->C;

  proc_table[p].wcet = et->C;

  /* Job insertion */

  job_task_default_model(job, et->dline);

  level_table[lev->scheduling_level]->

    private_insert(lev->scheduling_level, p, (TASK_MODEL *)&job);

  et->flags |= ELASTIC_JOB_PRESENT;

}

static void ELASTIC_timer_act(void *arg) {

  PID p = (PID)(arg);

  ELASTIC_level_des *lev;

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

  ELASTIC_task_descr *et = &lev->elist[p];

  /* Use the current deadline as the new activation time */

  ELASTIC_activation(lev, p, &et->dline);

  event_need_reschedule();

  /* Next activation */

  et->dltimer = kern_event_post(&et->dline, ELASTIC_timer_act, (void *)(p));

}

/* Check feasability and compute new utilizations for the task set */

static int ELASTIC_compress(ELASTIC_level_des *lev) {

  PID i;

  ELASTIC_task_descr *et;

  int ok;

  ext_bandwidth_t Umin;  // minimum utilization

  ext_bandwidth_t Umax;  // nominal (maximum) utilization of compressable tasks

  ext_bandwidth_t Uf;    // amount of non-compressable utilization

  int Ev;                // sum of elasticity among compressable tasks

  JOB_TASK_MODEL job;

  Umin = 0;

  Umax = 0;

  for (i=0; i<MAX_PROC; i++) {

    et = &lev->elist[i];

    if (et->flags & ELASTIC_PRESENT) {

      if (et->E == 0) {

        Umin += et->U;

        Umax += et->U;

      } else {

        Umin += et->Umin;

        Umax += et->Umax;

        et->U = et->Umax;   // reset previous saturations (if any)

      }

    }

  }

  if (Umin > lev->U) return -1;  // NOT FEASIBLE

  if (Umax <= lev->U) return 0;  // FEASIBLE WITH MAXIMUM UTILIZATIONS

  do {

    Uf = 0;

    Ev = 0;

    Umax = 0;

    for (i=0; i<MAX_PROC; i++) {

      et = &lev->elist[i];

      if (et->flags & ELASTIC_PRESENT) {

        if (et->E == 0 || et->U == et->Umin) {

          Uf += et->U;

        } else {

          Ev += et->E;

          Umax += et->Umax;

        }

      }

    }

    ok = 1;

    for (i=0; i<MAX_PROC; i++) {

      et = &lev->elist[i];

      if (et->flags & ELASTIC_PRESENT) {

        if (et->E > 0 && et->U > et->Umin) {

          et->U = et->Umax - (Umax - lev->U + Uf) * et->E / Ev;

          if (et->U < et->Umin) {

            et->U = et->Umin;

            ok = 0;

          }

        }

      }

    }

  } while (ok == 0);

  // Increase periods of compressed tasks IMMEDIATELY.

  // The other ones will be changed at their next activation

  for (i=0; i<MAX_PROC; i++) {

    et = &lev->elist[i];

    if (et->flags & ELASTIC_PRESENT) {

      if (et->U != et->oldU) {

        /* Utilization has been changed. Compute new period */

        et->T = ((long long)et->C * (long long)MAX_BANDWIDTH) / et->U;

      }

      if (et->U < et->oldU) {

        /* Task has been compressed. Change its deadline NOW! */

        if (et->flags & ELASTIC_JOB_PRESENT) {

          /* Remove job from level */

          level_table[lev->scheduling_level]->

            private_extract(lev->scheduling_level, i);

        }

        /* Compute new deadline */

        et->dline = et->release;

        ADDUSEC2TIMESPEC(et->T, &et->dline);

        if (et->dltimer != -1) {

          /* Delete old deadline timer, post new one */

          kern_event_delete(et->dltimer);

          et->dltimer = kern_event_post(&et->dline, ELASTIC_timer_act,(void *)(i));

        }

        if (et->flags & ELASTIC_JOB_PRESENT) {

          /* Reinsert job */

          job_task_default_model(job, et->dline);

          level_table[lev->scheduling_level]->

            private_insert(lev->scheduling_level, i, (TASK_MODEL *)&job);

        }

      }

      et->oldU = et->U;  /* Update oldU */

    }

  }

#ifdef ELASTIC_DEBUG

  cprintf("New periods: ");

  for (i=0; i<MAX_PROC; i++) {

    et = &lev->elist[i];

    if (et->flags & ELASTIC_PRESENT) {

      cprintf("%s:%d ", proc_table[i].name, (int)et->T);

    }

  }

  cprintf("\n");

#endif

  return 0; // FEASIBLE

}

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

static int ELASTIC_public_guarantee(LEVEL l, bandwidth_t *freebandwidth)

{

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

  if (*freebandwidth >= lev->U) {

    *freebandwidth -= (unsigned int)lev->U;

    return 1;

  } else {

    return 0;

  }

}

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

{

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

  ELASTIC_TASK_MODEL *elastic = (ELASTIC_TASK_MODEL *)m;

  ELASTIC_task_descr *et = &lev->elist[p];

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

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

  if (elastic->C == 0) return -1;

  if (elastic->Tmin > elastic->Tmax) return -1;

  if (elastic->Tmax == 0) return -1;

  if (elastic->Tmin == 0) return -1;

  NULL_TIMESPEC(&(et->dline));

  et->Tmin = elastic->Tmin;

  et->Tmax = elastic->Tmax;

  et->C = elastic->C;

  et->E = elastic->E;

  et->beta = elastic->beta;

  et->Umax = ((long long)MAX_BANDWIDTH * (long long)elastic->C) / elastic->Tmin;

  et->Umin = ((long long)MAX_BANDWIDTH * (long long)elastic->C) / elastic->Tmax;

  et->U = et->Umax;

  et->oldU = 0;

  et->T = et->Tmin;

  et->dltimer = -1;

  proc_table[p].avail_time = elastic->C;

  proc_table[p].wcet       = elastic->C;

  proc_table[p].control    |= CONTROL_CAP;

  return 0;

}

static void ELASTIC_public_detach(LEVEL l, PID p)

{

  //ELASTIC_level_des *lev = (ELASTIC_level_des *)(level_table[l]);

}

static int ELASTIC_public_eligible(LEVEL l, PID p)

{

  //ELASTIC_level_des *lev = (ELASTIC_level_des *)(level_table[l]);

  return 0;

}

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

{

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

  level_table[ lev->scheduling_level ]->

    private_dispatch(lev->scheduling_level,p,nostop);

}

static void ELASTIC_public_epilogue(LEVEL l, PID p)

{

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

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

  if (proc_table[p].avail_time <= 0) {

    TRACER_LOGEVENT(FTrace_EVT_task_wcet_violation,

                    (unsigned short int)proc_table[p].context,0);

    kern_raise(XWCET_VIOLATION,p);

  }

  level_table[lev->scheduling_level]->

      private_epilogue(lev->scheduling_level,p);

}

static void ELASTIC_public_activate(LEVEL l, PID p, struct timespec *t)

{

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

  ELASTIC_task_descr *et = &lev->elist[p];

  /* check if we are not in the SLEEP state */

  if (proc_table[p].status != SLEEP) {

    return;

  }

  et->flags |= ELASTIC_PRESENT;

  if (ELASTIC_compress(lev) == -1) {

    et->flags &= ~ELASTIC_PRESENT;

#ifdef ELASTIC_DEBUG

    cprintf("ELASTIC_public_activate: compression failed!\n");

#endif

    return;

  }

  ELASTIC_activation(lev,p,t);

  /* Next activation */

  et->dltimer = kern_event_post(&et->dline, ELASTIC_timer_act, (void *)(p));

}

static void ELASTIC_public_unblock(LEVEL l, PID p)

{

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

  struct timespec acttime;

  kern_gettime(&acttime);

  ELASTIC_activation(lev,p,&acttime);

}

static void ELASTIC_public_block(LEVEL l, PID p)

{

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

  ELASTIC_task_descr *et = &lev->elist[p];

  level_table[lev->scheduling_level]->

    private_extract(lev->scheduling_level,p);

  et->flags &= ~ELASTIC_JOB_PRESENT;

}

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

{

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

  ELASTIC_task_descr *et = &lev->elist[p];

  switch((long)(m)) {

    case (long)(NULL):

      level_table[lev->scheduling_level]->

        private_extract(lev->scheduling_level,p);

      et->flags &= ~ELASTIC_JOB_PRESENT;

      proc_table[p].status = ELASTIC_IDLE;

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

      TRACER_LOGEVENT(FTrace_EVT_task_end_cycle,(unsigned short int)proc_table[p].context,(unsigned int)l);

      break;

    case 1:

      level_table[ lev->scheduling_level ]->

        private_extract(lev->scheduling_level,p);

      et->flags &= ~ELASTIC_JOB_PRESENT;

      proc_table[p].status = SLEEP;

      TRACER_LOGEVENT(FTrace_EVT_task_disable,(unsigned short int)proc_table[p].context,(unsigned int)l);

      break;

  }

  return 0;

}

static void ELASTIC_public_end(LEVEL l, PID p)

{

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

  ELASTIC_task_descr *et = &lev->elist[p];

  level_table[ lev->scheduling_level ]->

    private_extract(lev->scheduling_level,p);

  et->flags &= ~ELASTIC_JOB_PRESENT;

}

/*+ Registration function +*/

LEVEL ELASTIC_register_level(int flags, LEVEL master, ext_bandwidth_t U)

{

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

  ELASTIC_level_des *lev;  /* for readableness only */

  PID i;

  printk("ELASTIC_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor(sizeof(ELASTIC_level_des));

  lev = (ELASTIC_level_des *)level_table[l];

  /* fill the standard descriptor */

  if (flags & ELASTIC_ENABLE_GUARANTEE)

    lev->l.public_guarantee = ELASTIC_public_guarantee;

  else

    lev->l.public_guarantee = NULL;

  lev->l.public_create    = ELASTIC_public_create;

  lev->l.public_detach    = ELASTIC_public_detach;

  lev->l.public_end       = ELASTIC_public_end;

  lev->l.public_eligible  = ELASTIC_public_eligible;

  lev->l.public_dispatch  = ELASTIC_public_dispatch;

  lev->l.public_epilogue  = ELASTIC_public_epilogue;

  lev->l.public_activate  = ELASTIC_public_activate;

  lev->l.public_unblock   = ELASTIC_public_unblock;

  lev->l.public_block     = ELASTIC_public_block;

  lev->l.public_message   = ELASTIC_public_message;

  /* fill the ELASTIC task descriptor part */

  for (i=0; i<MAX_PROC; i++) {

     NULL_TIMESPEC(&(lev->elist[i].dline));

     lev->elist[i].Tmin = 0;

     lev->elist[i].Tmax = 0;

     lev->elist[i].T = 0;

     lev->elist[i].U = 0;

     lev->elist[i].C = 0;

     lev->elist[i].E = 0;

     lev->elist[i].beta = 0;

     lev->elist[i].flags = 0;

  }

  lev->U = U;

  lev->scheduling_level = master;

  lev->current_level = l;

  lev->flags = 0;

  return l;

}

/* Force the period of task p to a given value */

int ELASTIC_set_period(PID p, TIME period) {

  SYS_FLAGS f;

  int saveE;          

  ext_bandwidth_t saveU;

  f = kern_fsave();

  ELASTIC_level_des *lev;

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

  ELASTIC_task_descr *et = &lev->elist[p];

  saveE = et->E;

  saveU = et->U;

  et->E = 0;  /* set elasticity to zero to force period */

  et->U = ((long long)MAX_BANDWIDTH * (long long)et->C)/period;

  if (ELASTIC_compress(lev) == -1) {

#ifdef ELASTIC_DEBUG

    cprintf("ELASTIC_set_period failed: could not compress\n");

#endif

    et->E = saveE;

    et->U = saveU;

    kern_frestore(f);

    return -1;

  }

  et->E = saveE;     /* Restore E when compression is done */

  kern_frestore(f);

  return 0;

}

int ELASTIC_get_period(PID p) {

  SYS_FLAGS f;

  ELASTIC_level_des *lev;

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

  TIME retval;

  f = kern_fsave();

  if (lev->elist[p].flags & ELASTIC_PRESENT) {  

    retval = lev->elist[p].T;

    kern_frestore(f);

    return retval;

  } else {

    kern_frestore(f);

    return -1;

  }

}

int ELASTIC_set_E(PID p, int E)

{

  SYS_FLAGS f;

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

  ELASTIC_task_descr *et = &lev->elist[p];

  int saveE;

  f = kern_fsave();

  if (et->flags & ELASTIC_PRESENT) {

    saveE = et->E;

    et->E = E;

    if (ELASTIC_compress(lev) == -1) {

#ifdef ELASTIC_DEBUG

      cprintf("ELASTIC_set_E failed: could not compress\n");

#endif

      et->E = saveE;

      kern_frestore(f);

      return -1;

    }

    kern_frestore(f);

    return 0;

  } else {

    kern_frestore(f);

    return -1;

  }

}

int ELASTIC_get_E(PID p) {

  SYS_FLAGS f;

  ELASTIC_level_des *lev;

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

  f = kern_fsave();

  if (lev->elist[p].flags & ELASTIC_PRESENT) {

    kern_frestore(f);

    return lev->elist[p].E;

  } else {

    kern_frestore(f);

    return -1;

  }

}

int ELASTIC_set_beta(PID p, int beta) {

  SYS_FLAGS f;

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

  ELASTIC_task_descr *et = &lev->elist[p];

  int saveBeta;

  f = kern_fsave();

  if (et->flags & ELASTIC_PRESENT) {

    saveBeta = et->beta;

    et->beta = beta;

    if (ELASTIC_compress(lev) == -1) {

#ifdef ELASTIC_DEBUG

      cprintf("ELASTIC_set_beta failed: could not compress\n");

#endif

      et->beta = saveBeta;

      kern_frestore(f);

      return -1;

    }

    kern_frestore(f);

    return 0;

  } else {

    kern_frestore(f);

    return -1;

  }

}

int ELASTIC_get_beta(PID p) {

  SYS_FLAGS f;

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

  int retval;

  f = kern_fsave();

  if (lev->elist[p].flags & ELASTIC_PRESENT) {

    retval = lev->elist[p].beta;

    kern_frestore(f);

    return retval;

  } else {

    kern_frestore(f);

    return -1;

  }

}

int ELASTIC_set_bandwidth(LEVEL level, ext_bandwidth_t U) {

  SYS_FLAGS f;

  ELASTIC_level_des *lev = (ELASTIC_level_des *)level_table[level];

  f = kern_fsave();

  lev->U = U;

  if (ELASTIC_compress(lev) == -1) {

#ifdef ELASTIC_DEBUG

    cprintf("ELASTIC_set_bandwidth failed: could not compress\n");

#endif

    kern_frestore(f);

    return -1;

  }

  kern_frestore(f);

  return 0;

}

ext_bandwidth_t ELASTIC_get_bandwidth(LEVEL level) {

  ELASTIC_level_des *lev = (ELASTIC_level_des *)level_table[level];;

  return lev->U;

}