WIP on hw3

pintos-env/pintos/threads/fpr_arith.h

@@ -0,0 +1,156 @@
+/*
+ * fpr_arith.h
+ *
+ *  Created on: 20/03/2013
+ *      Author: Eduardo Bezerra - kdubezerra@gmail.com
+ */
+
+#ifndef FPR_ARITH_H_
+#define FPR_ARITH_H_
+
+/* FIXED POINT REAL
+
+   This header contains the definition of the FPReal type, which
+   is a signed 32 bits integer. It has the following structure:
+
+   32 bits:
+      1 for sign
+      17 for integer part
+      14 for fractional part
+
+   See section B.6 of Pintos documentation for a detailed explanation:
+   http://www2.icorsi.ch/mod/resource/view.php?id=91264
+
+*/
+
+/* Fixed-point real type. */
+typedef int FPReal;
+
+/* Number of bits reserved for the fractional part. */
+#define FRACBITS 14
+
+/* Convert an FPReal to int */
+static inline int FPR_TO_INT (FPReal fpr);
+
+/* Convert an int to FPReal */
+static inline FPReal INT_TO_FPR (int);
+
+/* Increment an FPReal by 1 */
+static inline FPReal FPR_INC (FPReal *);
+
+/* Add two FPReals */
+static inline FPReal FPR_ADD_FPR (FPReal, FPReal);
+
+/* Subtract one FPReal from another */
+static inline FPReal FPR_SUB_FPR (FPReal, FPReal);
+
+/* Multiply an FPReal by an int */
+static inline FPReal FPR_MUL_INT (FPReal, int);
+
+/* Divide an FPReal by an int */
+static inline FPReal FPR_DIV_INT (FPReal, int);
+
+/* Add an int to an FPReal */
+static inline FPReal FPR_ADD_INT (FPReal, int);
+
+/* Subtract an int from an FPReal */
+static inline FPReal FPR_SUB_INT (FPReal, int);
+
+/* Multiply two FPReals */
+static inline FPReal FPR_MUL_FPR (FPReal, FPReal);
+
+/* Divide an FPReal by another */
+static inline FPReal FPR_DIV_FPR (FPReal, FPReal);
+
+/* Divide two ints and return the real result as an FPReal */
+static inline FPReal INT_DIV_INT (int, int);
+
+
+
+
+/* ==================================*/
+/* FPReal functions implementations. */
+
+/* Convert an FPReal to int */
+static inline int
+FPR_TO_INT (FPReal fpr) {
+   return fpr >> FRACBITS;
+}
+
+/* Convert an int to FPReal */
+static inline FPReal
+INT_TO_FPR (int i) {
+   return i << FRACBITS;
+}
+
+/* Increment an FPReal by 1 */
+static inline
+FPReal FPR_INC (FPReal * fpr) {
+   (*fpr) += (1 << FRACBITS);
+   return *fpr;
+}
+
+/* Add two FPReals */
+static inline
+FPReal FPR_ADD_FPR (FPReal fpr_a, FPReal fpr_b) {
+   return fpr_a + fpr_b;
+}
+
+/* Subtract one FPReal from another */
+static inline
+FPReal FPR_SUB_FPR (FPReal fpr_a, FPReal fpr_b) {
+   return fpr_a - fpr_b;
+}
+
+/* Multiply an FPReal by an int */
+static inline
+FPReal FPR_MUL_INT (FPReal fpr_a, int b) {
+   return fpr_a * b;
+}
+
+/* Divide an FPReal by an int */
+static inline
+FPReal FPR_DIV_INT (FPReal fpr_a, int b) {
+   return fpr_a / b;
+}
+
+/* Add an int to an FPReal */
+static inline
+FPReal FPR_ADD_INT (FPReal fpr_a, int b) {
+   return fpr_a + (b << FRACBITS);
+}
+
+/* Subtract an int from an FPReal */
+static inline
+FPReal FPR_SUB_INT (FPReal fpr_a, int b) {
+   return fpr_a - (b << FRACBITS);
+}
+
+/* Multiply two FPReals */
+static inline
+FPReal FPR_MUL_FPR (FPReal fpr_a, FPReal fpr_b) {
+   int64_t extended_a = fpr_a;
+   extended_a *= (int64_t) fpr_b;
+   extended_a >>= FRACBITS;
+   return (FPReal) extended_a;
+}
+
+/* Divide an FPReal by another */
+static inline
+FPReal FPR_DIV_FPR (FPReal fpr_a, FPReal fpr_b) {
+   int64_t extended_a = fpr_a;
+   extended_a <<= FRACBITS;
+   extended_a /= (int64_t) fpr_b;
+   return (FPReal) extended_a;
+}
+
+/* Divide two ints and return the real result as an FPReal */
+static inline
+FPReal INT_DIV_INT (int a, int b) {
+   int64_t exta = a;
+   exta <<= FRACBITS;
+   exta /= b;
+   return (FPReal) exta;
+}
+
+#endif /* FPR_ARITH_H_ */

pintos-env/pintos/threads/thread.c

@@ -43,6 +43,8 @@ static struct lock tid_lock;
 
 static struct list sleeping;
 
+static FPReal load_avg;
+
 /* Stack frame for kernel_thread(). */
 struct kernel_thread_frame
   {
@@ -76,6 +78,9 @@ static void *alloc_frame (struct thread *, size_t size);
 static void schedule (void);
 void thread_schedule_tail (struct thread *prev);
 static tid_t allocate_tid (void);
+void thread_yield_for_higher_priority(void);
+static void compute_mlfqs_priority(struct thread* t);
+bool comp_priority(struct list_elem *, struct list_elem *, void *);
 
 /* Initializes the threading system by transforming the code
    that's currently running into a thread.  This can't work in
@@ -106,6 +111,7 @@ thread_init (void)
   initial_thread->tid = allocate_tid ();
 
   list_init(&sleeping);
+  load_avg = INT_TO_FPR(0);
 }
 
 static bool
@@ -163,6 +169,8 @@ thread_start (void)
   sema_down (&idle_started);
 }
 
+static int tick_count = 0;
+
 /* Called by the timer interrupt handler at each timer tick.
    Thus, this function runs in an external interrupt context. */
 void
@@ -180,11 +188,77 @@ thread_tick (void)
   else
     kernel_ticks++;
 
+  ++thread_ticks;
+  ++tick_count;
+
+  if (thread_mlfqs) {
+    if (thread_ticks % 4 == 0) {
+      compute_mlfqs_priority(t);
+    }
+    t->recent_cpu = FPR_ADD_INT(t->recent_cpu, 1);
+
+    if (tick_count >= TIMER_FREQ) { // this is true every second
+      tick_count = 0;
+
+      int thr_running = thread_current() == idle_thread ? 0 : 1;
+      thr_running += list_size(&ready_list);
+
+      load_avg = FPR_ADD_FPR(
+          FPR_MUL_FPR(INT_DIV_INT(59, 60), load_avg),
+          FPR_MUL_INT(INT_DIV_INT(1, 60), thr_running));
+
+      FPReal dag = FPR_MUL_INT(load_avg, 2);
+
+      t->recent_cpu = FPR_MUL_FPR(t->recent_cpu,
+          FPR_DIV_FPR(dag, FPR_ADD_INT(dag, 1))) + INT_TO_FPR(t->nice);
+
+      if (t->recent_cpu > INT_TO_FPR(100)) {
+        t->recent_cpu = INT_TO_FPR(100);
+      } else if (t->recent_cpu < INT_TO_FPR(0)) {
+        t->recent_cpu = INT_TO_FPR(0);
+      }
+
+      printf("recent_cpu: %d\n", t->recent_cpu);
+      //printf("load_avg: %d - threads_ready: %d\n", load_avg, thr_running);
+    }
+  }
+
   /* Enforce preemption. */
-  if (++thread_ticks >= TIME_SLICE)
+  if (thread_ticks >= TIME_SLICE)
     intr_yield_on_return ();
 }
 
+int
+thread_get_nice (void)
+{
+  return thread_current()->nice;
+}
+
+void
+thread_set_nice (int nice)
+{
+  struct thread* t = thread_current();
+
+  enum intr_level old_level = intr_disable();
+  t->nice = nice > 20 || nice < -20 ? 0 : nice;
+  compute_mlfqs_priority(t);
+  intr_set_level(old_level);
+
+  thread_yield_for_higher_priority();
+}
+
+int
+thread_get_recent_cpu (void)
+{
+  return FPR_TO_INT(FPR_MUL_INT(thread_current()->recent_cpu, 100));
+}
+
+int
+thread_get_load_avg (void)
+{
+  return FPR_TO_INT(FPR_MUL_INT(load_avg, 100));
+}
+
 /* Prints thread statistics. */
 void
 thread_print_stats (void)
@@ -255,6 +329,8 @@ thread_create (const char *name, int priority,
   /* Add to run queue. */
   thread_unblock (t);
 
+  thread_yield_for_higher_priority();
+
   return tid;
 }
 
@@ -385,51 +461,19 @@ thread_foreach (thread_action_func *func, void *aux)
     }
 }
 
+int
+thread_get_priority (void) {
+  return thread_current()->priority;
+}
+
 /* Sets the current thread's priority to NEW_PRIORITY. */
 void
 thread_set_priority (int new_priority)
 {
   thread_current ()->priority = new_priority;
+  thread_yield_for_higher_priority();
 }
 
-/* Returns the current thread's priority. */
-int
-thread_get_priority (void)
-{
-  return thread_current ()->priority;
-}
-
-/* Sets the current thread's nice value to NICE. */
-void
-thread_set_nice (int nice UNUSED)
-{
-  /* Not yet implemented. */
-}
-
-/* Returns the current thread's nice value. */
-int
-thread_get_nice (void)
-{
-  /* Not yet implemented. */
-  return 0;
-}
-
-/* Returns 100 times the system load average. */
-int
-thread_get_load_avg (void)
-{
-  /* Not yet implemented. */
-  return 0;
-}
-
-/* Returns 100 times the current thread's recent_cpu value. */
-int
-thread_get_recent_cpu (void)
-{
-  /* Not yet implemented. */
-  return 0;
-}
-
 /* Idle thread.  Executes when no other thread is ready to run.
 
    The idle thread is initially put on the ready list by
@@ -500,6 +544,15 @@ is_thread (struct thread *t)
   return t != NULL && t->magic == THREAD_MAGIC;
 }
 
+static void
+compute_mlfqs_priority(struct thread* t) {
+  t->priority = PRI_MAX - FPR_TO_INT(FPR_DIV_INT(t->recent_cpu, 4))
+    - (t->nice * 2);
+
+  if (t->priority < PRI_MIN) t->priority = PRI_MIN;
+  else if (t->priority > PRI_MAX) t->priority = PRI_MAX;
+}
+
 /* Does basic initialization of T as a blocked thread named
    NAME. */
 static void
@@ -513,7 +566,16 @@ init_thread (struct thread *t, const char *name, int priority)
   t->status = THREAD_BLOCKED;
   strlcpy (t->name, name, sizeof t->name);
   t->stack = (uint8_t *) t + PGSIZE;
-  t->priority = priority;
+
+  if (thread_mlfqs) {
+    t->nice_init = priority > 20 || priority < 20 ? 0 : priority;
+    t->nice = t->nice_init;
+    t->recent_cpu = 0;
+    compute_mlfqs_priority(t);
+  } else {
+    t->priority = priority;
+  }
+
   t->magic = THREAD_MAGIC;
   list_push_back (&all_list, &t->allelem);
 }
@@ -541,8 +603,36 @@ next_thread_to_run (void)
 {
   if (list_empty (&ready_list))
     return idle_thread;
-  else
-    return list_entry (list_pop_front (&ready_list), struct thread, elem);
+  else {
+    // return list_entry (list_pop_front (&ready_list), struct thread, elem);
+
+    struct list_elem * th_max_elem = list_max(&ready_list, comp_priority, NULL);
+    struct thread * th_max = list_entry(th_max_elem, struct thread, elem);
+    list_remove(th_max_elem);
+    return th_max;
+  }
+}
+
+bool comp_priority(struct list_elem * a, struct list_elem * b, void *aux) {
+  struct thread * at = list_entry(a, struct thread, elem);
+  struct thread * bt = list_entry(b, struct thread, elem);
+
+  return at -> priority < bt -> priority;
+}
+
+void thread_yield_for_higher_priority(void) {
+  enum intr_level old_level = intr_disable();
+
+  if (!list_empty(&ready_list)) {
+    struct list_elem * th_max_elem = list_max(&ready_list, comp_priority, NULL);
+    struct thread * th_max = list_entry(th_max_elem, struct thread, elem);
+
+    struct thread * th_cur = thread_current();
+    if (th_cur -> priority < th_max -> priority)
+      thread_yield();
+  }
+
+intr_set_level(old_level);
 }
 
 /* Completes a thread switch by activating the new thread's page

pintos-env/pintos/threads/thread.h

@@ -7,6 +7,7 @@
 #include <debug.h>
 #include <list.h>
 #include <stdint.h>
+#include "threads/fpr_arith.h"
 
 /* States in a thread's life cycle. */
 enum thread_status
@@ -95,6 +96,9 @@ struct thread
     uint64_t wakeup;
     /* Shared between thread.c and synch.c. */
     struct list_elem elem;              /* List element. */
+    int nice;
+    int nice_init;
+    FPReal recent_cpu;
 
 #ifdef USERPROG
     /* Owned by userprog/process.c. */