gettime.c

   1 /*
   2  * Clock functions
   3  */
   4
   5 #include <unistd.h>
   6 #include <sys/time.h>
   7
   8 #include "fio.h"
   9 #include "smalloc.h"
  10
  11 #include "hash.h"
  12
  13 static int clock_gettime_works;
  14 static struct timeval last_tv;
  15 static int last_tv_valid;
  16
  17 static struct timeval *fio_tv;
  18 int fio_gtod_offload = 0;
  19 int fio_gtod_cpu = -1;
  20
  21 #ifdef FIO_DEBUG_TIME
  22
  23 #define HASH_BITS       8
  24 #define HASH_SIZE       (1 << HASH_BITS)
  25
  26 static struct flist_head hash[HASH_SIZE];
  27 static int gtod_inited;
  28
  29 struct gtod_log {
  30         struct flist_head list;
  31         void *caller;
  32         unsigned long calls;
  33 };
  34
  35 static struct gtod_log *find_hash(void *caller)
  36 {
  37         unsigned long h = hash_ptr(caller, HASH_BITS);
  38         struct flist_head *entry;
  39
  40         flist_for_each(entry, &hash[h]) {
  41                 struct gtod_log *log = flist_entry(entry, struct gtod_log,
  42                                                                         list);
  43
  44                 if (log->caller == caller)
  45                         return log;
  46         }
  47
  48         return NULL;
  49 }
  50
  51 static struct gtod_log *find_log(void *caller)
  52 {
  53         struct gtod_log *log = find_hash(caller);
  54
  55         if (!log) {
  56                 unsigned long h;
  57
  58                 log = malloc(sizeof(*log));
  59                 INIT_FLIST_HEAD(&log->list);
  60                 log->caller = caller;
  61                 log->calls = 0;
  62
  63                 h = hash_ptr(caller, HASH_BITS);
  64                 flist_add_tail(&log->list, &hash[h]);
  65         }
  66
  67         return log;
  68 }
  69
  70 static void gtod_log_caller(void *caller)
  71 {
  72         if (gtod_inited) {
  73                 struct gtod_log *log = find_log(caller);
  74
  75                 log->calls++;
  76         }
  77 }
  78
  79 static void fio_exit fio_dump_gtod(void)
  80 {
  81         unsigned long total_calls = 0;
  82         int i;
  83
  84         for (i = 0; i < HASH_SIZE; i++) {
  85                 struct flist_head *entry;
  86                 struct gtod_log *log;
  87
  88                 flist_for_each(entry, &hash[i]) {
  89                         log = flist_entry(entry, struct gtod_log, list);
  90
  91                         printf("function %p, calls %lu\n", log->caller,
  92                                                                 log->calls);
  93                         total_calls += log->calls;
  94                 }
  95         }
  96
  97         printf("Total %lu gettimeofday\n", total_calls);
  98 }
  99
 100 static void fio_init gtod_init(void)
 101 {
 102         int i;
 103
 104         for (i = 0; i < HASH_SIZE; i++)
 105                 INIT_FLIST_HEAD(&hash[i]);
 106
 107         gtod_inited = 1;
 108 }
 109
 110 #endif /* FIO_DEBUG_TIME */
 111
 112 #ifdef FIO_DEBUG_TIME
 113 void fio_gettime(struct timeval *tp, void *caller)
 114 #else
 115 void fio_gettime(struct timeval *tp, void fio_unused *caller)
 116 #endif
 117 {
 118 #ifdef FIO_DEBUG_TIME
 119         if (!caller)
 120                 caller = __builtin_return_address(0);
 121
 122         gtod_log_caller(caller);
 123 #endif
 124         if (fio_tv) {
 125                 memcpy(tp, fio_tv, sizeof(*tp));
 126                 return;
 127         } else if (!clock_gettime_works) {
 128 gtod:
 129                 gettimeofday(tp, NULL);
 130         } else {
 131                 struct timespec ts;
 132
 133                 if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
 134                         clock_gettime_works = 0;
 135                         goto gtod;
 136                 }
 137
 138                 tp->tv_sec = ts.tv_sec;
 139                 tp->tv_usec = ts.tv_nsec / 1000;
 140         }
 141
 142         /*
 143          * If Linux is using the tsc clock on non-synced processors,
 144          * sometimes time can appear to drift backwards. Fix that up.
 145          */
 146         if (last_tv_valid) {
 147                 if (tp->tv_sec < last_tv.tv_sec)
 148                         tp->tv_sec = last_tv.tv_sec;
 149                 else if (last_tv.tv_sec == tp->tv_sec &&
 150                          tp->tv_usec < last_tv.tv_usec)
 151                         tp->tv_usec = last_tv.tv_usec;
 152         }
 153         last_tv_valid = 1;
 154         memcpy(&last_tv, tp, sizeof(*tp));
 155 }
 156
 157 void fio_gtod_init(void)
 158 {
 159         fio_tv = smalloc(sizeof(struct timeval));
 160         assert(fio_tv);
 161 }
 162
 163 void fio_gtod_update(void)
 164 {
 165         gettimeofday(fio_tv, NULL);
 166 }