[mirror_ubuntu-bionic-kernel.git] / tools / testing / selftests / timers / nsleep-lat.c

/* Measure nanosleep timer latency
 *              by: john stultz (john.stultz@linaro.org)
 *		(C) Copyright Linaro 2013
 *              Licensed under the GPLv2
 *
 *  To build:
 *	$ gcc nsleep-lat.c -o nsleep-lat -lrt
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <string.h>
#include <signal.h>
#include "../kselftest.h"

#define NSEC_PER_SEC 1000000000ULL

#define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */


#define CLOCK_REALTIME			0
#define CLOCK_MONOTONIC			1
#define CLOCK_PROCESS_CPUTIME_ID	2
#define CLOCK_THREAD_CPUTIME_ID		3
#define CLOCK_MONOTONIC_RAW		4
#define CLOCK_REALTIME_COARSE		5
#define CLOCK_MONOTONIC_COARSE		6
#define CLOCK_BOOTTIME			7
#define CLOCK_REALTIME_ALARM		8
#define CLOCK_BOOTTIME_ALARM		9
#define CLOCK_HWSPECIFIC		10
#define CLOCK_TAI			11
#define NR_CLOCKIDS			12

#define UNSUPPORTED 0xf00f

char *clockstring(int clockid)
{
	switch (clockid) {
	case CLOCK_REALTIME:
		return "CLOCK_REALTIME";
	case CLOCK_MONOTONIC:
		return "CLOCK_MONOTONIC";
	case CLOCK_PROCESS_CPUTIME_ID:
		return "CLOCK_PROCESS_CPUTIME_ID";
	case CLOCK_THREAD_CPUTIME_ID:
		return "CLOCK_THREAD_CPUTIME_ID";
	case CLOCK_MONOTONIC_RAW:
		return "CLOCK_MONOTONIC_RAW";
	case CLOCK_REALTIME_COARSE:
		return "CLOCK_REALTIME_COARSE";
	case CLOCK_MONOTONIC_COARSE:
		return "CLOCK_MONOTONIC_COARSE";
	case CLOCK_BOOTTIME:
		return "CLOCK_BOOTTIME";
	case CLOCK_REALTIME_ALARM:
		return "CLOCK_REALTIME_ALARM";
	case CLOCK_BOOTTIME_ALARM:
		return "CLOCK_BOOTTIME_ALARM";
	case CLOCK_TAI:
		return "CLOCK_TAI";
	};
	return "UNKNOWN_CLOCKID";
}

struct timespec timespec_add(struct timespec ts, unsigned long long ns)
{
	ts.tv_nsec += ns;
	while (ts.tv_nsec >= NSEC_PER_SEC) {
		ts.tv_nsec -= NSEC_PER_SEC;
		ts.tv_sec++;
	}
	return ts;
}


long long timespec_sub(struct timespec a, struct timespec b)
{
	long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;

	ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
	return ret;
}

int nanosleep_lat_test(int clockid, long long ns)
{
	struct timespec start, end, target;
	long long latency = 0;
	int i, count;

	target.tv_sec = ns/NSEC_PER_SEC;
	target.tv_nsec = ns%NSEC_PER_SEC;

	if (clock_gettime(clockid, &start))
		return UNSUPPORTED;
	if (clock_nanosleep(clockid, 0, &target, NULL))
		return UNSUPPORTED;

	count = 10;

	/* First check relative latency */
	clock_gettime(clockid, &start);
	for (i = 0; i < count; i++)
		clock_nanosleep(clockid, 0, &target, NULL);
	clock_gettime(clockid, &end);

	if (((timespec_sub(start, end)/count)-ns) > UNRESONABLE_LATENCY) {
		printf("Large rel latency: %lld ns :", (timespec_sub(start, end)/count)-ns);
		return -1;
	}

	/* Next check absolute latency */
	for (i = 0; i < count; i++) {
		clock_gettime(clockid, &start);
		target = timespec_add(start, ns);
		clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL);
		clock_gettime(clockid, &end);
		latency += timespec_sub(target, end);
	}

	if (latency/count > UNRESONABLE_LATENCY) {
		printf("Large abs latency: %lld ns :", latency/count);
		return -1;
	}

	return 0;
}


int main(int argc, char **argv)
{
	long long length;
	int clockid, ret;

	for (clockid = CLOCK_REALTIME; clockid < NR_CLOCKIDS; clockid++) {

		/* Skip cputime clockids since nanosleep won't increment cputime */
		if (clockid == CLOCK_PROCESS_CPUTIME_ID ||
				clockid == CLOCK_THREAD_CPUTIME_ID ||
				clockid == CLOCK_HWSPECIFIC)
			continue;

		printf("nsleep latency %-26s ", clockstring(clockid));
		fflush(stdout);

		length = 10;
		while (length <= (NSEC_PER_SEC * 10)) {
			ret = nanosleep_lat_test(clockid, length);
			if (ret)
				break;
			length *= 100;

		}

		if (ret == UNSUPPORTED) {
			printf("[UNSUPPORTED]\n");
			continue;
		}
		if (ret < 0) {
			printf("[FAILED]\n");
			return ksft_exit_fail();
		}
		printf("[OK]\n");
	}
	return ksft_exit_pass();
}
Commit	Line	Data
c5fffcb2 JS	1	/* Measure nanosleep timer latency
	2	* by: john stultz (john.stultz@linaro.org)
	3	* (C) Copyright Linaro 2013
	4	* Licensed under the GPLv2
	5	*
	6	* To build:
	7	* $ gcc nsleep-lat.c -o nsleep-lat -lrt
	8	*
	9	* This program is free software: you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation, either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*/
	19
	20	#include <stdio.h>
	21	#include <stdlib.h>
	22	#include <time.h>
	23	#include <sys/time.h>
	24	#include <sys/timex.h>
	25	#include <string.h>
	26	#include <signal.h>
c5fffcb2	27	#include "../kselftest.h"
c5fffcb2 JS	28
	29	#define NSEC_PER_SEC 1000000000ULL
	30
	31	#define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
	32
	33
	34	#define CLOCK_REALTIME 0
	35	#define CLOCK_MONOTONIC 1
	36	#define CLOCK_PROCESS_CPUTIME_ID 2
	37	#define CLOCK_THREAD_CPUTIME_ID 3
	38	#define CLOCK_MONOTONIC_RAW 4
	39	#define CLOCK_REALTIME_COARSE 5
	40	#define CLOCK_MONOTONIC_COARSE 6
	41	#define CLOCK_BOOTTIME 7
	42	#define CLOCK_REALTIME_ALARM 8
	43	#define CLOCK_BOOTTIME_ALARM 9
	44	#define CLOCK_HWSPECIFIC 10
	45	#define CLOCK_TAI 11
	46	#define NR_CLOCKIDS 12
	47
	48	#define UNSUPPORTED 0xf00f
	49
	50	char *clockstring(int clockid)
	51	{
	52	switch (clockid) {
	53	case CLOCK_REALTIME:
	54	return "CLOCK_REALTIME";
	55	case CLOCK_MONOTONIC:
	56	return "CLOCK_MONOTONIC";
	57	case CLOCK_PROCESS_CPUTIME_ID:
	58	return "CLOCK_PROCESS_CPUTIME_ID";
	59	case CLOCK_THREAD_CPUTIME_ID:
	60	return "CLOCK_THREAD_CPUTIME_ID";
	61	case CLOCK_MONOTONIC_RAW:
	62	return "CLOCK_MONOTONIC_RAW";
	63	case CLOCK_REALTIME_COARSE:
	64	return "CLOCK_REALTIME_COARSE";
	65	case CLOCK_MONOTONIC_COARSE:
	66	return "CLOCK_MONOTONIC_COARSE";
	67	case CLOCK_BOOTTIME:
	68	return "CLOCK_BOOTTIME";
	69	case CLOCK_REALTIME_ALARM:
	70	return "CLOCK_REALTIME_ALARM";
	71	case CLOCK_BOOTTIME_ALARM:
	72	return "CLOCK_BOOTTIME_ALARM";
	73	case CLOCK_TAI:
	74	return "CLOCK_TAI";
	75	};
	76	return "UNKNOWN_CLOCKID";
	77	}
	78
	79	struct timespec timespec_add(struct timespec ts, unsigned long long ns)
	80	{
	81	ts.tv_nsec += ns;
	82	while (ts.tv_nsec >= NSEC_PER_SEC) {
	83	ts.tv_nsec -= NSEC_PER_SEC;
	84	ts.tv_sec++;
	85	}
	86	return ts;
	87	}
	88
	89
	90	long long timespec_sub(struct timespec a, struct timespec b)
	91	{
92	long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
93
94	ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
95	return ret;
96	}
97
98	int nanosleep_lat_test(int clockid, long long ns)
99	{
100	struct timespec start, end, target;
101	long long latency = 0;
102	int i, count;
103
104	target.tv_sec = ns/NSEC_PER_SEC;
105	target.tv_nsec = ns%NSEC_PER_SEC;
106
107	if (clock_gettime(clockid, &start))
108	return UNSUPPORTED;
109	if (clock_nanosleep(clockid, 0, &target, NULL))
110	return UNSUPPORTED;
111
112	count = 10;
113
114	/* First check relative latency */
115	clock_gettime(clockid, &start);
116	for (i = 0; i < count; i++)
117	clock_nanosleep(clockid, 0, &target, NULL);
118	clock_gettime(clockid, &end);
119
120	if (((timespec_sub(start, end)/count)-ns) > UNRESONABLE_LATENCY) {
121	printf("Large rel latency: %lld ns :", (timespec_sub(start, end)/count)-ns);
122	return -1;
123	}
124
125	/* Next check absolute latency */
126	for (i = 0; i < count; i++) {
127	clock_gettime(clockid, &start);
128	target = timespec_add(start, ns);
129	clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL);
130	clock_gettime(clockid, &end);
131	latency += timespec_sub(target, end);
132	}
133
134	if (latency/count > UNRESONABLE_LATENCY) {
135	printf("Large abs latency: %lld ns :", latency/count);
136	return -1;
137	}
138
139	return 0;
140	}
141
142
143
144	int main(int argc, char **argv)
145	{
146	long long length;
147	int clockid, ret;
148
149	for (clockid = CLOCK_REALTIME; clockid < NR_CLOCKIDS; clockid++) {
150
151	/* Skip cputime clockids since nanosleep won't increment cputime */
152	if (clockid == CLOCK_PROCESS_CPUTIME_ID \|\|
153	clockid == CLOCK_THREAD_CPUTIME_ID \|\|
154	clockid == CLOCK_HWSPECIFIC)
155	continue;
156
157	printf("nsleep latency %-26s ", clockstring(clockid));
19de0f85	158	fflush(stdout);
c5fffcb2 JS	159
	160	length = 10;
	161	while (length <= (NSEC_PER_SEC * 10)) {
	162	ret = nanosleep_lat_test(clockid, length);
	163	if (ret)
	164	break;
	165	length *= 100;
	166
	167	}
	168
	169	if (ret == UNSUPPORTED) {
	170	printf("[UNSUPPORTED]\n");
	171	continue;
	172	}
	173	if (ret < 0) {
	174	printf("[FAILED]\n");
	175	return ksft_exit_fail();
	176	}
	177	printf("[OK]\n");
	178	}
	179	return ksft_exit_pass();
	180	}