src/k8clock.c

   1 #include <ctype.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5
   6 #include "k8clock.h"
   7
   8
   9 k8clock_type k8clock_initialized = K8CLOCK_ERROR;
  10 k8clock_t clk;
  11
  12
  13 #ifndef CLOCK_MONOTONIC_RAW
  14 # define K8CLOCK_CLOCK_TYPE  CLOCK_MONOTONIC_RAW
  15 #else
  16 # define K8CLOCK_CLOCK_TYPE  CLOCK_MONOTONIC
  17 #endif
  18
  19
  20 static k8clock_type k8clock_check_source (void) {
  21   FILE *fl = fopen("/sys/devices/system/clocksource/clocksource0/current_clocksource", "r");
  22   char buf[128];
  23   if (fl == NULL) {
  24     fprintf(stderr, "WARNING: can't determine clock source!\n");
  25     return K8CLOCK_OTHER;
  26   }
  27   memset(buf, 0, sizeof(buf));
  28   if (fgets(buf, sizeof(buf)-1, fl) == NULL) {
  29     fclose(fl);
  30     fprintf(stderr, "WARNING: can't determine clock source!\n");
  31     return K8CLOCK_OTHER;
  32   }
  33   fclose(fl);
  34   while (buf[0] && isspace(buf[strlen(buf)-1])) buf[strlen(buf)-1] = 0;
  35   //fprintf(stderr, "clock source: %s\n", buf);
  36   return (strcasecmp(buf, "hpet") == 0 ? K8CLOCK_HPET : K8CLOCK_OTHER);
  37 }
  38
  39
  40 __attribute__((constructor)) static void k8clock_ctor (void) {
  41   if (k8clock_initialized == K8CLOCK_ERROR) {
  42     struct timespec cres;
  43     k8clock_initialized = k8clock_check_source();
  44     if (clock_getres(K8CLOCK_CLOCK_TYPE, &cres) != 0) {
  45       fprintf(stderr, "ERROR: can't get clock resolution!\n");
  46       k8clock_initialized = K8CLOCK_ERROR;
  47       return;
  48     }
  49     //fprintf(stderr, "CLOCK_MONOTONIC: %ld:%ld\n", cres.tv_sec, cres.tv_nsec);
  50     if (cres.tv_sec > 0 || cres.tv_nsec > (long)1000000*10 /*10 ms*/) {
  51       fprintf(stderr, "ERROR: real-time clock resolution is too low!\n");
  52       k8clock_initialized = K8CLOCK_ERROR;
  53       return;
  54     }
  55     k8clock_init(&clk);
  56   }
  57 }
  58
  59
  60 void k8clock_init (k8clock_t *clk) {
  61   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  62     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &clk->stt) != 0) {
  63       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  64     }
  65   }
  66 }
  67
  68
  69 uint64_t k8clock_ms (k8clock_t *clk) {
  70   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  71     struct timespec ts;
  72     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &ts) != 0) {
  73       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  74       return 0;
  75     }
  76     // ah, ignore nanoseconds in clk->stt here: we need only 'differential' time, and it can start with something weird
  77     return ((int64_t)(ts.tv_sec-clk->stt.tv_sec))*1000+(ts.tv_nsec-clk->stt.tv_nsec)/1000000+1;
  78   }
  79   return 0;
  80 }
  81
  82
  83 uint64_t k8clock_micro (k8clock_t *clk) {
  84   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  85     struct timespec ts;
  86     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &ts) != 0) {
  87       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  88       return 0;
  89     }
  90     // ah, ignore nanoseconds in clk->stt here: we need only 'differential' time, and it can start with something weird
  91     return ((int64_t)(ts.tv_sec-clk->stt.tv_sec))*1000000+(ts.tv_nsec-clk->stt.tv_nsec)/1000+1;
  92   }
  93   return 0;
  94 }
  95
  96
  97 uint64_t k8clock (void) {
  98   return k8clock_ms(&clk);
  99 }
 100
 101
 102 uint64_t k8clockmicro (void) {
 103   return k8clock_micro(&clk);
 104 }