include/linux/ckrm_sched.h

   1 /* include/linux/ckrm_sched.h - Supports CKRM scheduling
   2  *
   3  * Copyright (C) Haoqiang Zheng,  IBM Corp. 2004
   4  * Copyright (C) Hubertus Franke,  IBM Corp. 2004
   5  *
   6  * Latest version, more details at http://ckrm.sf.net
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  */
  14
  15 #ifndef _CKRM_SCHED_H
  16 #define _CKRM_SCHED_H
  17
  18 #include <linux/sched.h>
  19 #include <linux/ckrm_rc.h>
  20 #include <linux/ckrm_classqueue.h>
  21
  22 #define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
  23
  24 struct prio_array {
  25         unsigned int nr_active;
  26         unsigned long bitmap[BITMAP_SIZE];
  27         struct list_head queue[MAX_PRIO];
  28 };
  29
  30 #ifdef CONFIG_CKRM_CPU_SCHEDULE
  31 #define rq_active(p,rq)   (get_task_lrq(p)->active)
  32 #define rq_expired(p,rq)  (get_task_lrq(p)->expired)
  33 int __init init_ckrm_sched_res(void);
  34 #else
  35 #define rq_active(p,rq)   (rq->active)
  36 #define rq_expired(p,rq)  (rq->expired)
  37 static inline void init_ckrm_sched_res(void) {}
  38 static inline int ckrm_cpu_monitor_init(void) {return 0;}
  39 #endif
  40
  41 #ifdef CONFIG_CKRM_CPU_SCHEDULE
  42 struct ckrm_runqueue {
  43         cq_node_t classqueue_linkobj;   /*links in classqueue */
  44         struct ckrm_cpu_class *cpu_class;       // class it belongs to
  45         struct classqueue_struct *classqueue;   // classqueue it belongs tow
  46         unsigned long long uncounted_ns;
  47
  48         prio_array_t *active, *expired, arrays[2];
  49         /*
  50            set to 0 on init, become null or array switch
  51            set to jiffies whenever an non-interactive job expires
  52            reset to jiffies if expires
  53          */
  54         unsigned long expired_timestamp;
  55
  56         /*
  57          * highest priority of tasks in active
  58          * initialized to be MAX_PRIO
  59          * updated on enqueue, dequeue
  60          */
  61         int top_priority;
  62         CVT_t local_cvt;
  63
  64         unsigned long lrq_load;
  65         int local_weight;
  66
  67
  68         /*
  69          * unused CPU time accumulated while thoe class
  70          * is inactive goes to savings
  71          *
  72          * initialized to be 0
  73          * a class can't accumulate more than SAVING_THRESHOLD of savings
  74          * savings are kept in normalized form (like cvt)
  75          * so when task share change the savings should be scaled accordingly
  76          */
  77         unsigned long long savings;
  78
  79         unsigned long magic;    //for debugging
  80 };
  81
  82 typedef struct ckrm_runqueue ckrm_lrq_t;
  83
  84 /**
  85  * ckrm_cpu_class_stat - cpu usage statistics maintained for each class
  86  *
  87  */
  88 struct ckrm_cpu_class_stat {
  89         spinlock_t stat_lock;
  90
  91         unsigned long long total_ns;    /*how much nano-secs it has consumed */
  92
  93         struct ckrm_cpu_demand_stat local_stats[NR_CPUS];
  94
  95         /*
  96          *
  97          */
  98         unsigned long max_demand; /* the maximun a class can consume */
  99         int egrt,megrt; /*effective guarantee*/
 100         int ehl,mehl; /*effective hard limit, my effective hard limit*/
 101
 102         /*
 103          * eshare: for both default class and its children
 104          * meshare: just for the default class
 105          */
 106         int eshare;
 107         int meshare;
 108 };
 109
 110 #define CKRM_CPU_CLASS_MAGIC 0x7af2abe3
 111
 112 #define USAGE_SAMPLE_FREQ HZ  //sample every 1 seconds
 113 #define NS_PER_SAMPLE (USAGE_SAMPLE_FREQ*(NSEC_PER_SEC/HZ))
 114 #define USAGE_WINDOW_SIZE 60  //keep the last 60 sample
 115
 116 struct ckrm_usage {
 117         unsigned long samples[USAGE_WINDOW_SIZE]; //record usages
 118         unsigned long sample_pointer; //pointer for the sliding window
 119         unsigned long long last_ns; //ns for last sample
 120         unsigned long long last_sample_jiffies; //in number of jiffies
 121 };
 122
 123 /*
 124  * manages the class status
 125  * there should be only one instance of this object for each class in the whole system
 126  */
 127 struct ckrm_cpu_class {
 128         struct ckrm_core_class *core;
 129         struct ckrm_core_class *parent;
 130         struct ckrm_shares shares;
 131         spinlock_t cnt_lock;    // always grab parent's lock first and then child's
 132         struct ckrm_cpu_class_stat stat;
 133         struct list_head links; // for linking up in cpu classes
 134         ckrm_lrq_t local_queues[NR_CPUS];       // runqueues
 135         struct ckrm_usage usage;
 136         unsigned long magic;    //for debugging
 137 };
 138
 139 #define cpu_class_weight(cls) (cls->stat.meshare)
 140 #define local_class_weight(lrq) (lrq->local_weight)
 141
 142 static inline int valid_cpu_class(struct ckrm_cpu_class * cls)
 143 {
 144         return (cls && cls->magic == CKRM_CPU_CLASS_MAGIC);
 145 }
 146
 147 struct classqueue_struct *get_cpu_classqueue(int cpu);
 148 struct ckrm_cpu_class * get_default_cpu_class(void);
 149
 150
 151 static inline void ckrm_usage_init(struct ckrm_usage* usage)
 152 {
 153         int i;
 154
 155         for (i=0; i < USAGE_WINDOW_SIZE; i++)
 156                 usage->samples[i] = 0;
 157         usage->sample_pointer = 0;
 158         usage->last_ns = 0;
 159         usage->last_sample_jiffies = 0;
 160 }
 161
 162 /*
 163  * this function can be called at any frequency
 164  * it's self-contained
 165  */
 166 static inline void ckrm_sample_usage(struct ckrm_cpu_class* clsptr)
 167 {
 168         struct ckrm_usage* usage = &clsptr->usage;
 169         unsigned long long cur_sample;
 170         int duration = jiffies - usage->last_sample_jiffies;
 171
 172 //      printk("\tckrm_sample_usage %ld %p: %lld\n",jiffies, clsptr,cur_sample);
 173
 174         if (duration < USAGE_SAMPLE_FREQ)
 175                 return;
 176
 177         cur_sample = clsptr->stat.total_ns - usage->last_ns;
 178         //scale it based on the sample duration
 179         cur_sample *= ((duration << 10)/USAGE_SAMPLE_FREQ);
 180         cur_sample >>= 10;
 181
 182         usage->samples[usage->sample_pointer++] = cur_sample;
 183         usage->last_sample_jiffies = jiffies;
 184         usage->last_ns = clsptr->stat.total_ns;
 185         if (usage->sample_pointer >= USAGE_WINDOW_SIZE)
 186                 usage->sample_pointer = 0;
 187 }
 188
 189 //duration is specified in number of jiffies
 190 //return the usage in percentage
 191 static inline int get_ckrm_usage(struct ckrm_cpu_class* clsptr, int duration)
 192 {
 193         int nr_samples = duration/USAGE_SAMPLE_FREQ?:1;
 194         struct ckrm_usage* usage = &clsptr->usage;
 195         unsigned long long total = 0;
 196         int i, idx;
 197
 198         if (nr_samples > USAGE_WINDOW_SIZE)
 199                 nr_samples = USAGE_WINDOW_SIZE;
 200
 201         idx = usage->sample_pointer;
 202         for (i = 0; i< nr_samples; i++) {
 203                 if (! idx)
 204                         idx = USAGE_WINDOW_SIZE;
 205                 idx --;
 206                 total += usage->samples[idx];
 207         }
 208         total *= 100;
 209         do_div(total,nr_samples);
 210         do_div(total,NS_PER_SAMPLE);
 211         // printk("percent %lld\n",total);
 212         return total;
 213 }
 214
 215
 216 #define lrq_nr_running(lrq) \
 217              (lrq->active->nr_active + lrq->expired->nr_active)
 218
 219 static inline ckrm_lrq_t *
 220 get_ckrm_lrq(struct ckrm_cpu_class*cls, int cpu)
 221 {
 222         return &(cls->local_queues[cpu]);
 223 }
 224
 225 static inline ckrm_lrq_t *get_task_lrq(struct task_struct *p)
 226 {
 227         return &(p->cpu_class->local_queues[task_cpu(p)]);
 228 }
 229
 230 #define task_list_entry(list)  list_entry(list,struct task_struct,run_list)
 231 #define class_list_entry(list) list_entry(list,struct ckrm_runqueue,classqueue_linkobj)
 232
 233 /* some additional interfaces exported from sched.c */
 234 struct runqueue;
 235 extern rwlock_t class_list_lock;
 236 extern struct list_head active_cpu_classes;
 237 unsigned int task_timeslice(task_t *p);
 238 void _ckrm_cpu_change_class(task_t *task, struct ckrm_cpu_class *newcls);
 239
 240 void init_cpu_classes(void);
 241 void init_cpu_class(struct ckrm_cpu_class *cls,ckrm_shares_t* shares);
 242 void ckrm_cpu_change_class(void *task, void *old, void *new);
 243
 244
 245 #define CPU_DEMAND_ENQUEUE 0
 246 #define CPU_DEMAND_DEQUEUE 1
 247 #define CPU_DEMAND_DESCHEDULE 2
 248 #define CPU_DEMAND_INIT 3
 249
 250 /*functions exported by ckrm_cpu_monitor.c*/
 251 void ckrm_cpu_monitor(void);
 252 int ckrm_cpu_monitor_init(void);
 253 void ckrm_cpu_stat_init(struct ckrm_cpu_class_stat *stat);
 254 void cpu_demand_event(struct ckrm_cpu_demand_stat* local_stat, int event, unsigned long long len);
 255 void adjust_local_weight(void);
 256
 257 #define get_task_lrq_stat(p) (&(p)->cpu_class->stat.local_stats[task_cpu(p)])
 258 #define get_cls_local_stat(cls,cpu) (&(cls)->stat.local_stats[cpu])
 259 #define get_rq_local_stat(lrq,cpu) (get_cls_local_stat((lrq)->cpu_class,cpu))
 260
 261 #define CLASS_QUANTIZER 22      //shift from ns to increase class bonus
 262 #define PRIORITY_QUANTIZER 0    //controls how much a high prio task can borrow
 263 #define CKRM_SHARE_ACCURACY 10
 264 #define NSEC_PER_MS 1000000
 265 #define NSEC_PER_JIFFIES (NSEC_PER_SEC/HZ)
 266
 267
 268 #define MAX_SAVINGS_ABSOLUTE (10LLU*NSEC_PER_SEC)  // 10 seconds
 269
 270 #define CVT_UPDATE_TICK     ((HZ/2)?:1)
 271
 272 // ABSOLUTE_CKRM_TUNING determines whether classes can make up
 273 // lost time in absolute time or in relative values
 274
 275 #define ABSOLUTE_CKRM_TUNING         // preferred due to more predictable behavior
 276
 277 #ifdef ABSOLUTE_CKRM_TUNING
 278
 279 #define MAX_SAVINGS        MAX_SAVINGS_ABSOLUTE
 280 //an absolute bonus of 200ms for classes when reactivated
 281 #define INTERACTIVE_BONUS(lrq) ((200*NSEC_PER_MS)/local_class_weight(lrq))
 282 #define SAVINGS_LEAK_SPEED (CVT_UPDATE_TICK/10*NSEC_PER_JIFFIES)
 283
 284 #define scale_cvt(val,lrq)   ((val)*local_class_weight(lrq))
 285 #define unscale_cvt(val,lrq) (do_div(val,local_class_weight(lrq)))
 286
 287 #else
 288
 289 #define MAX_SAVINGS (MAX_SAVINGS_ABSOLUTE >> CKRM_SHARE_ACCURACY)
 290 /*
 291  * to improve system responsiveness
 292  * an inactive class is put a little bit ahead of the current class when it wakes up
 293  * the amount is set in normalized termis to simplify the calculation
 294  * for class with 100% share, it can be 2s ahead
 295  * while for class with 10% share, it can be 200ms ahead
 296  */
 297 #define INTERACTIVE_BONUS(lrq) (2*NSEC_PER_MS)
 298
 299 /*
 300  * normalized savings can't be more than MAX_NORMALIZED_SAVINGS
 301  * based on the current configuration
 302  * this means that a class with share 100% will accumulate 10s at most
 303  * while a class with 1% of the share can only accumulate 100ms
 304  */
 305
 306 //a class with share 100% can get 100ms every 500ms
 307 //while a class with share 10% can only get 10ms every 500ms
 308 #define SAVINGS_LEAK_SPEED ((CVT_UPDATE_TICK/5*NSEC_PER_JIFFIES) >> CKRM_SHARE_ACCURACY)
 309
 310 #define scale_cvt(val,lrq)   (val)
 311 #define unscale_cvt(val,lrq) (val)
 312
 313 #endif
 314
 315
 316 /**
 317  * get_effective_prio: return the effective priority of a class local queue
 318  *
 319  * class priority = progress * a + urgency * b
 320  * progress = queue cvt
 321  * urgency = queue top priority
 322  * a and b are scaling factors
 323  * currently, prio increases by 1 if either: top_priority increase by one
 324  *                                   or, local_cvt increases by 4ms
 325  */
 326 static inline int get_effective_prio(ckrm_lrq_t * lrq)
 327 {
 328         int prio;
 329
 330         prio = lrq->local_cvt >> CLASS_QUANTIZER;  // cumulative usage
 331         prio += lrq->top_priority >> PRIORITY_QUANTIZER; // queue urgency
 332
 333         return prio;
 334 }
 335
 336 CVT_t get_local_cur_cvt(int cpu);
 337
 338 /**
 339  * update_class_priority:
 340  *
 341  * called whenever cvt or top_priority changes
 342  *
 343  * internal: (calling structure)
 344  * update_class_priority
 345  *   -- set_top_priority
 346  *      -- class_enqueue_task
 347  *      -- class_dequeue_task
 348  *      -- rq_get_next_task (queue switch)
 349  *   -- update_local_cvt
 350  *      -- schedule
 351  */
 352 static inline void update_class_priority(ckrm_lrq_t *local_rq)
 353 {
 354         int effective_prio = get_effective_prio(local_rq);
 355         classqueue_update_prio(local_rq->classqueue,
 356                                &local_rq->classqueue_linkobj,
 357                                effective_prio);
 358 }
 359
 360 /*
 361  *  set the new top priority and reposition the queue
 362  *  called when: task enqueue/dequeue and queue switch
 363  */
 364 static inline void set_top_priority(ckrm_lrq_t *lrq,
 365                                     int new_priority)
 366 {
 367         lrq->top_priority = new_priority;
 368         update_class_priority(lrq);
 369 }
 370
 371 /*
 372  * task_load: how much load this task counts
 373  */
 374 static inline unsigned long task_load(struct task_struct* p)
 375 {
 376         return (task_timeslice(p) * p->demand_stat.cpu_demand);
 377 }
 378
 379 /*
 380  * runqueue load is the local_weight of all the classes on this cpu
 381  * must be called with class_list_lock held
 382  */
 383 static inline unsigned long ckrm_cpu_load(int cpu)
 384 {
 385         struct ckrm_cpu_class *clsptr;
 386         ckrm_lrq_t* lrq;
 387         struct ckrm_cpu_demand_stat* l_stat;
 388         int total_load = 0;
 389         int load;
 390
 391         list_for_each_entry(clsptr,&active_cpu_classes,links) {
 392                 lrq =  get_ckrm_lrq(clsptr,cpu);
 393                 l_stat = get_cls_local_stat(clsptr,cpu);
 394                 load = lrq->local_weight;
 395                 if (l_stat->cpu_demand < load)
 396                         load = l_stat->cpu_demand;
 397                 total_load += load;
 398         }
 399         return total_load;
 400 }
 401
 402 static inline void class_enqueue_task(struct task_struct *p,
 403                                       prio_array_t * array)
 404 {
 405         ckrm_lrq_t *lrq;
 406         int effective_prio;
 407
 408         lrq = get_task_lrq(p);
 409
 410         cpu_demand_event(&p->demand_stat,CPU_DEMAND_ENQUEUE,0);
 411         lrq->lrq_load += task_load(p);
 412
 413         if ((p->prio < lrq->top_priority) && (array == lrq->active))
 414                 set_top_priority(lrq, p->prio);
 415
 416         if (! cls_in_classqueue(&lrq->classqueue_linkobj)) {
 417                 cpu_demand_event(get_task_lrq_stat(p),CPU_DEMAND_ENQUEUE,0);
 418                 effective_prio = get_effective_prio(lrq);
 419                 classqueue_enqueue(lrq->classqueue, &lrq->classqueue_linkobj, effective_prio);
 420         }
 421
 422 }
 423
 424 static inline void class_dequeue_task(struct task_struct *p,
 425                                       prio_array_t * array)
 426 {
 427         ckrm_lrq_t *lrq = get_task_lrq(p);
 428         unsigned long load = task_load(p);
 429
 430         BUG_ON(lrq->lrq_load < load);
 431         lrq->lrq_load -= load;
 432
 433         cpu_demand_event(&p->demand_stat,CPU_DEMAND_DEQUEUE,0);
 434
 435         if ((array == lrq->active) && (p->prio == lrq->top_priority)
 436             && list_empty(&(array->queue[p->prio])))
 437                 set_top_priority(lrq,
 438                                  find_next_bit(array->bitmap, MAX_PRIO,
 439                                                p->prio));
 440 }
 441
 442 /*
 443  *  called after a task is switched out. Update the local cvt accounting
 444  *  we need to stick with long instead of long long due to nonexistent 64-bit division
 445  */
 446 static inline void update_local_cvt(struct task_struct *p, unsigned long nsec)
 447 {
 448         ckrm_lrq_t * lrq = get_task_lrq(p);
 449
 450         unsigned long cvt_inc = nsec / local_class_weight(lrq);
 451
 452         lrq->local_cvt += cvt_inc;
 453         lrq->uncounted_ns += nsec;
 454
 455         update_class_priority(lrq);
 456 }
 457
 458 static inline int class_preempts_curr(struct task_struct * p, struct task_struct* curr)
 459 {
 460         struct cq_node_struct* node1 = &(get_task_lrq(p)->classqueue_linkobj);
 461         struct cq_node_struct* node2 = &(get_task_lrq(curr)->classqueue_linkobj);
 462
 463         return (class_compare_prio(node1,node2) < 0);
 464 }
 465
 466 /*
 467  * return a random value with range [0, (val-1)]
 468  */
 469 static inline int get_ckrm_rand(unsigned long val)
 470 {
 471         int rand;
 472         static int last_rand[NR_CPUS];
 473         int cpu = smp_processor_id();
 474
 475         rand = last_rand[cpu];
 476         rand ++;
 477         if (rand >= val)
 478                 rand = 0;
 479
 480         last_rand[cpu] = rand;
 481         return rand;
 482 }
 483
 484 void update_class_cputime(int this_cpu);
 485
 486 /**********************************************/
 487 /*          PID_LOAD_BALANCING                */
 488 /**********************************************/
 489 struct ckrm_load_struct {
 490         unsigned long load_p;   /*propotional*/
 491         unsigned long load_i;   /*integral   */
 492         long load_d;   /*derivative */
 493 };
 494
 495 typedef struct ckrm_load_struct ckrm_load_t;
 496
 497 static inline void ckrm_load_init(ckrm_load_t* ckrm_load) {
 498         ckrm_load->load_p = 0;
 499         ckrm_load->load_i = 0;
 500         ckrm_load->load_d = 0;
 501 }
 502
 503 void ckrm_load_sample(ckrm_load_t* ckrm_load,int cpu);
 504 long pid_get_pressure(ckrm_load_t* ckrm_load, int local_group);
 505 #define rq_ckrm_load(rq) (&((rq)->ckrm_load))
 506
 507 static inline void ckrm_sched_tick(int j,int this_cpu,struct ckrm_load_struct* ckrm_load)
 508 {
 509         read_lock(&class_list_lock);
 510
 511 #ifdef CONFIG_SMP
 512         ckrm_load_sample(ckrm_load,this_cpu);
 513 #endif
 514
 515         if (!(j % CVT_UPDATE_TICK)) {
 516                 classqueue_update_base(get_cpu_classqueue(this_cpu));
 517                 update_class_cputime(this_cpu);
 518         }
 519
 520         read_unlock(&class_list_lock);
 521 }
 522
 523 #endif /*CONFIG_CKRM_CPU_SCHEDULE */
 524
 525 #endif