mirror of
https://codeberg.org/redict/redict.git
synced 2025-01-22 08:08:53 -05:00
68 lines
2.4 KiB
C
68 lines
2.4 KiB
C
// SPDX-FileCopyrightText: 2024 Redict Contributors
|
|
// SPDX-FileCopyrightText: 2024 Salvatore Sanfilippo <antirez at gmail dot com>
|
|
//
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
// SPDX-License-Identifier: LGPL-3.0-only
|
|
|
|
#ifndef __MONOTONIC_H
|
|
#define __MONOTONIC_H
|
|
/* The monotonic clock is an always increasing clock source. It is unrelated to
|
|
* the actual time of day and should only be used for relative timings. The
|
|
* monotonic clock is also not guaranteed to be chronologically precise; there
|
|
* may be slight skew/shift from a precise clock.
|
|
*
|
|
* Depending on system architecture, the monotonic time may be able to be
|
|
* retrieved much faster than a normal clock source by using an instruction
|
|
* counter on the CPU. On x86 architectures (for example), the RDTSC
|
|
* instruction is a very fast clock source for this purpose.
|
|
*/
|
|
|
|
#include "fmacros.h"
|
|
#include <stdint.h>
|
|
#include <unistd.h>
|
|
|
|
/* A counter in micro-seconds. The 'monotime' type is provided for variables
|
|
* holding a monotonic time. This will help distinguish & document that the
|
|
* variable is associated with the monotonic clock and should not be confused
|
|
* with other types of time.*/
|
|
typedef uint64_t monotime;
|
|
|
|
/* Retrieve counter of micro-seconds relative to an arbitrary point in time. */
|
|
extern monotime (*getMonotonicUs)(void);
|
|
|
|
typedef enum monotonic_clock_type {
|
|
MONOTONIC_CLOCK_POSIX,
|
|
MONOTONIC_CLOCK_HW,
|
|
} monotonic_clock_type;
|
|
|
|
/* Call once at startup to initialize the monotonic clock. Though this only
|
|
* needs to be called once, it may be called additional times without impact.
|
|
* Returns a printable string indicating the type of clock initialized.
|
|
* (The returned string is static and doesn't need to be freed.) */
|
|
const char *monotonicInit(void);
|
|
|
|
/* Return a string indicating the type of monotonic clock being used. */
|
|
const char *monotonicInfoString(void);
|
|
|
|
/* Return the type of monotonic clock being used. */
|
|
monotonic_clock_type monotonicGetType(void);
|
|
|
|
/* Functions to measure elapsed time. Example:
|
|
* monotime myTimer;
|
|
* elapsedStart(&myTimer);
|
|
* while (elapsedMs(myTimer) < 10) {} // loops for 10ms
|
|
*/
|
|
static inline void elapsedStart(monotime *start_time) {
|
|
*start_time = getMonotonicUs();
|
|
}
|
|
|
|
static inline uint64_t elapsedUs(monotime start_time) {
|
|
return getMonotonicUs() - start_time;
|
|
}
|
|
|
|
static inline uint64_t elapsedMs(monotime start_time) {
|
|
return elapsedUs(start_time) / 1000;
|
|
}
|
|
|
|
#endif
|