git.ozlabs.org Git - ccan/blob - ccan/likely/likely.c

   1 #ifdef CCAN_LIKELY_DEBUG
   2 #include <ccan/likely/likely.h>
   3 #include <ccan/hash/hash.h>
   4 #include <ccan/htable/htable.h>
   5 #include <stdlib.h>
   6 #include <stdio.h>
   7 static struct htable *htable;
   8
   9 struct trace {
  10         const char *condstr;
  11         const char *file;
  12         unsigned int line;
  13         bool expect;
  14         unsigned long count, right;
  15 };
  16
  17 /* We hash the pointers, which will be identical for same call. */
  18 static unsigned long hash_trace(const struct trace *trace)
  19 {
  20         return hash_pointer(trace->condstr,
  21                             hash_pointer(trace->file,
  22                                          trace->line + trace->expect));
  23 }
  24
  25 static bool hash_cmp(const void *htelem, void *cmpdata)
  26 {
  27         const struct trace *t1 = htelem, *t2 = cmpdata;
  28         return t1->condstr == t2->condstr
  29                 && t1->file == t2->file
  30                 && t1->line == t2->line
  31                 && t1->expect == t2->expect;
  32 }
  33
  34 static size_t rehash(const void *elem, void *priv)
  35 {
  36         return hash_trace(elem);
  37 }
  38
  39 static void init_trace(struct trace *trace,
  40                        const char *condstr, const char *file, unsigned int line,
  41                        bool expect)
  42 {
  43         trace->condstr = condstr;
  44         trace->file = file;
  45         trace->line = line;
  46         trace->expect = expect;
  47         trace->count = trace->right = 0;
  48 }
  49
  50 static struct trace *add_trace(const char *condstr,
  51                                const char *file, unsigned int line, bool expect)
  52 {
  53         struct trace *trace = malloc(sizeof(*trace));
  54         init_trace(trace, condstr, file, line, expect);
  55         htable_add(htable, hash_trace(trace), trace);
  56         return trace;
  57 }
  58
  59 long _likely_trace(bool cond, bool expect,
  60                    const char *condstr,
  61                    const char *file, unsigned int line)
  62 {
  63         struct trace *p, trace;
  64
  65         if (!htable)
  66                 htable = htable_new(rehash, NULL);
  67
  68         init_trace(&trace, condstr, file, line, expect);
  69         p = htable_get(htable, hash_trace(&trace), hash_cmp, &trace);
  70         if (!p)
  71                 p = add_trace(condstr, file, line, expect);
  72
  73         p->count++;
  74         if (cond == expect)
  75                 p->right++;
  76
  77         return cond;
  78 }
  79
  80 struct get_stats_info {
  81         struct trace *worst;
  82         unsigned int min_hits;
  83         double worst_ratio;
  84 };
  85
  86 static double right_ratio(const struct trace *t)
  87 {
  88         return (double)t->right / t->count;
  89 }
  90
  91 static void get_stats(struct trace *trace, struct get_stats_info *info)
  92 {
  93         if (trace->count < info->min_hits)
  94                 return;
  95
  96         if (right_ratio(trace) < info->worst_ratio) {
  97                 info->worst = trace;
  98                 info->worst_ratio = right_ratio(trace);
  99         }
 100 }
 101
 102 const char *likely_stats(unsigned int min_hits, unsigned int percent)
 103 {
 104         struct get_stats_info info;
 105         struct htable_iter i;
 106         char *ret;
 107         struct trace *trace;
 108
 109         if (!htable)
 110                 return NULL;
 111
 112         info.min_hits = min_hits;
 113         info.worst = NULL;
 114         info.worst_ratio = 2;
 115
 116         /* This is O(n), but it's not likely called that often. */
 117         for (trace = htable_first(htable, &i);
 118              trace;
 119              trace = htable_next(htable,&i)) {
 120                 get_stats(trace, &info);
 121         }
 122
 123         if (info.worst_ratio * 100 > percent)
 124                 return NULL;
 125
 126         ret = malloc(strlen(info.worst->condstr) +
 127                      strlen(info.worst->file) +
 128                      sizeof(long int) * 8 +
 129                      sizeof("%s:%u:%slikely(%s) correct %u%% (%lu/%lu)"));
 130         sprintf(ret, "%s:%u:%slikely(%s) correct %u%% (%lu/%lu)",
 131                 info.worst->file, info.worst->line,
 132                 info.worst->expect ? "" : "un", info.worst->condstr,
 133                 (unsigned)(info.worst_ratio * 100),
 134                 info.worst->right, info.worst->count);
 135
 136         htable_del(htable, hash_trace(info.worst), info.worst);
 137         free(info.worst);
 138
 139         return ret;
 140 }
 141 #endif /*CCAN_LIKELY_DEBUG*/