include/lttng/ust-clock.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2014  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #ifndef LTTNG_UST_CLOCK_H
   8 #define LTTNG_UST_CLOCK_H
   9
  10 #include <stdint.h>
  11 #include <stddef.h>
  12
  13 /*
  14  * Set each callback for the trace clock override, and then enable the
  15  * override. Those functions return negative error values on error, 0 on
  16  * success.
  17  */
  18
  19 typedef uint64_t (*lttng_ust_clock_read64_function)(void);
  20 typedef uint64_t (*lttng_ust_clock_freq_function)(void);
  21 typedef int (*lttng_ust_clock_uuid_function)(char *uuid);
  22 typedef const char *(*lttng_ust_clock_name_function)(void);
  23 typedef const char *(*lttng_ust_clock_description_function)(void);
  24
  25 /*
  26  * Set/Get clock override read callback. This callback should return the
  27  * current clock time (a 64-bit monotonic counter).
  28  */
  29 int lttng_ust_trace_clock_set_read64_cb(lttng_ust_clock_read64_function read64_cb);
  30 int lttng_ust_trace_clock_get_read64_cb(lttng_ust_clock_read64_function *read64_cb);
  31
  32 /*
  33  * Set/Get clock override frequency callback. This callback should return
  34  * the frequency of the clock in cycles per second.
  35  */
  36 int lttng_ust_trace_clock_set_freq_cb(lttng_ust_clock_freq_function freq_cb);
  37 int lttng_ust_trace_clock_get_freq_cb(lttng_ust_clock_freq_function *freq_cb);
  38
  39 /*
  40  * Set/Get clock override unique identifier.
  41  * LTTNG_UST_UUID_STR_LEN is the maximum length of uuid string. Includes
  42  * final \0.
  43  */
  44 #define LTTNG_UST_UUID_STR_LEN         37
  45
  46 int lttng_ust_trace_clock_set_uuid_cb(lttng_ust_clock_uuid_function uuid_cb);
  47 int lttng_ust_trace_clock_get_uuid_cb(lttng_ust_clock_uuid_function *uuid_cb);
  48
  49 /*
  50  * Set/Get clock override name.
  51  */
  52 int lttng_ust_trace_clock_set_name_cb(lttng_ust_clock_name_function name_cb);
  53 int lttng_ust_trace_clock_get_name_cb(lttng_ust_clock_name_function *name_cb);
  54
  55 /*
  56  * Set/Get clock override description.
  57  */
  58 int lttng_ust_trace_clock_set_description_cb(lttng_ust_clock_description_function description_cb);
  59 int lttng_ust_trace_clock_get_description_cb(lttng_ust_clock_description_function *description_cb);
  60
  61 /*
  62  * Use the clock override rather than the default clock.
  63  */
  64 int lttng_ust_enable_trace_clock_override(void);
  65
  66 #endif /* LTTNG_UST_CLOCK_H */