kernel/debug.c

   1 /* This file implements kernel debugging functionality that is not included
   2  * in the standard kernel. Available functionality includes timing of lock
   3  * functions and sanity checking of the scheduling queues.
   4  */
   5
   6 #include "kernel.h"
   7 #include "proc.h"
   8 #include "debug.h"
   9 #include <limits.h>
  10
  11 #if DEBUG_TIME_LOCKS            /* only include code if enabled */
  12
  13 /* Data structures to store lock() timing data. */
  14 struct lock_timingdata timingdata[TIMING_CATEGORIES];
  15 static unsigned long starttimes[TIMING_CATEGORIES][2];
  16
  17 #define HIGHCOUNT       0
  18 #define LOWCOUNT        1
  19
  20 void timer_start(int cat, char *name)
  21 {
  22         static int init = 0;
  23         unsigned long h, l;
  24         int i;
  25
  26         if (cat < 0 || cat >= TIMING_CATEGORIES) return;
  27
  28         for(i = 0; i < sizeof(timingdata[0].names) && *name; i++)
  29                 timingdata[cat].names[i] = *name++;
  30         timingdata[cat].names[sizeof(timingdata[0].names)-1] = '\0';
  31
  32         if (starttimes[cat][HIGHCOUNT]) {  return; }
  33
  34         if (!init) {
  35                 int t, f;
  36                 init = 1;
  37                 for(t = 0; t < TIMING_CATEGORIES; t++) {
  38                         timingdata[t].lock_timings_range[0] = 0;
  39                         timingdata[t].resets = timingdata[t].misses =
  40                                 timingdata[t].measurements = 0;
  41                 }
  42         }
  43
  44         read_tsc(&starttimes[cat][HIGHCOUNT], &starttimes[cat][LOWCOUNT]);
  45 }
  46
  47 void timer_end(int cat)
  48 {
  49         unsigned long h, l, d = 0, binsize;
  50         int bin;
  51
  52         read_tsc(&h, &l);
  53         if (cat < 0 || cat >= TIMING_CATEGORIES) return;
  54         if (!starttimes[cat][HIGHCOUNT]) {
  55                 timingdata[cat].misses++;
  56                 return;
  57         }
  58         if (starttimes[cat][HIGHCOUNT] == h) {
  59                 d = (l - starttimes[cat][1]);
  60         } else if (starttimes[cat][HIGHCOUNT] == h-1 &&
  61                 starttimes[cat][LOWCOUNT] > l) {
  62                 d = ((ULONG_MAX - starttimes[cat][LOWCOUNT]) + l);
  63         } else {
  64                 timingdata[cat].misses++;
  65                 return;
  66         }
  67         starttimes[cat][HIGHCOUNT] = 0;
  68         if (!timingdata[cat].lock_timings_range[0] ||
  69                 d < timingdata[cat].lock_timings_range[0] ||
  70                 d > timingdata[cat].lock_timings_range[1]) {
  71                 int t;
  72                 if (!timingdata[cat].lock_timings_range[0] ||
  73                         d < timingdata[cat].lock_timings_range[0])
  74                         timingdata[cat].lock_timings_range[0] = d;
  75                 if (!timingdata[cat].lock_timings_range[1] ||
  76                         d > timingdata[cat].lock_timings_range[1])
  77                         timingdata[cat].lock_timings_range[1] = d;
  78                 for(t = 0; t < TIMING_POINTS; t++)
  79                         timingdata[cat].lock_timings[t] = 0;
  80                 timingdata[cat].binsize =
  81                         (timingdata[cat].lock_timings_range[1] -
  82                         timingdata[cat].lock_timings_range[0])/(TIMING_POINTS+1);
  83                 if (timingdata[cat].binsize < 1)
  84                   timingdata[cat].binsize = 1;
  85                 timingdata[cat].resets++;
  86         }
  87         bin = (d-timingdata[cat].lock_timings_range[0]) /
  88                 timingdata[cat].binsize;
  89         if (bin < 0 || bin >= TIMING_POINTS) {
  90                 int t;
  91                 /* this indicates a bug, but isn't really serious */
  92                 for(t = 0; t < TIMING_POINTS; t++)
  93                         timingdata[cat].lock_timings[t] = 0;
  94                 timingdata[cat].misses++;
  95         } else {
  96                 timingdata[cat].lock_timings[bin]++;
  97                 timingdata[cat].measurements++;
  98         }
  99
 100         return;
 101 }
 102
 103 #endif /* DEBUG_TIME_LOCKS */
 104
 105 #if DEBUG_SCHED_CHECK           /* only include code if enabled */
 106
 107 #define PROCLIMIT 10000
 108
 109 PUBLIC void
 110 check_runqueues(char *when)
 111 {
 112   int q, l = 0;
 113   register struct proc *xp;
 114
 115   for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
 116         xp->p_found = 0;
 117         if (l++ > PROCLIMIT) {  panic("check error", NO_NUM); }
 118   }
 119
 120   for (q=0; q < NR_SCHED_QUEUES; q++) {
 121     if (rdy_head[q] && !rdy_tail[q]) {
 122         kprintf("head but no tail: %s", when);
 123                  panic("scheduling error", NO_NUM);
 124     }
 125     if (!rdy_head[q] && rdy_tail[q]) {
 126         kprintf("tail but no head: %s", when);
 127                  panic("scheduling error", NO_NUM);
 128     }
 129     if (rdy_tail[q] && rdy_tail[q]->p_nextready != NIL_PROC) {
 130         kprintf("tail and tail->next not null; %s", when);
 131                  panic("scheduling error", NO_NUM);
 132     }
 133     for(xp = rdy_head[q]; xp != NIL_PROC; xp = xp->p_nextready) {
 134         if (!xp->p_ready) {
 135                 kprintf("scheduling error: unready on runq: %s\n", when);
 136
 137                 panic("found unready process on run queue", NO_NUM);
 138         }
 139         if (xp->p_priority != q) {
 140                 kprintf("scheduling error: wrong priority: %s\n", when);
 141
 142                 panic("wrong priority", NO_NUM);
 143         }
 144         if (xp->p_found) {
 145                 kprintf("scheduling error: double scheduling: %s\n", when);
 146                 panic("proc more than once on scheduling queue", NO_NUM);
 147         }
 148         xp->p_found = 1;
 149         if (xp->p_nextready == NIL_PROC && rdy_tail[q] != xp) {
 150                 kprintf("scheduling error: last element not tail: %s\n", when);
 151                 panic("scheduling error", NO_NUM);
 152         }
 153         if (l++ > PROCLIMIT) panic("loop in schedule queue?", NO_NUM);
 154     }
 155   }
 156
 157   for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
 158         if (! isemptyp(xp) && xp->p_ready && ! xp->p_found) {
 159                 kprintf("scheduling error: ready not on queue: %s\n", when);
 160                 panic("ready proc not on scheduling queue", NO_NUM);
 161                 if (l++ > PROCLIMIT) { panic("loop in proc.t?", NO_NUM); }
 162         }
 163   }
 164 }
 165
 166 #endif /* DEBUG_SCHED_CHECK */