1c5fffcb2SJohn Stultz /* Measure nanosleep timer latency
2c5fffcb2SJohn Stultz * by: john stultz (john.stultz@linaro.org)
3c5fffcb2SJohn Stultz * (C) Copyright Linaro 2013
4c5fffcb2SJohn Stultz * Licensed under the GPLv2
5c5fffcb2SJohn Stultz *
6c5fffcb2SJohn Stultz * To build:
7c5fffcb2SJohn Stultz * $ gcc nsleep-lat.c -o nsleep-lat -lrt
8c5fffcb2SJohn Stultz *
9c5fffcb2SJohn Stultz * This program is free software: you can redistribute it and/or modify
10c5fffcb2SJohn Stultz * it under the terms of the GNU General Public License as published by
11c5fffcb2SJohn Stultz * the Free Software Foundation, either version 2 of the License, or
12c5fffcb2SJohn Stultz * (at your option) any later version.
13c5fffcb2SJohn Stultz *
14c5fffcb2SJohn Stultz * This program is distributed in the hope that it will be useful,
15c5fffcb2SJohn Stultz * but WITHOUT ANY WARRANTY; without even the implied warranty of
16c5fffcb2SJohn Stultz * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17c5fffcb2SJohn Stultz * GNU General Public License for more details.
18c5fffcb2SJohn Stultz */
19c5fffcb2SJohn Stultz
20c5fffcb2SJohn Stultz #include <stdio.h>
21c5fffcb2SJohn Stultz #include <stdlib.h>
22c5fffcb2SJohn Stultz #include <time.h>
23c5fffcb2SJohn Stultz #include <sys/time.h>
24c5fffcb2SJohn Stultz #include <sys/timex.h>
25c5fffcb2SJohn Stultz #include <string.h>
26c5fffcb2SJohn Stultz #include <signal.h>
27c5fffcb2SJohn Stultz #include "../kselftest.h"
28c5fffcb2SJohn Stultz
29c5fffcb2SJohn Stultz #define NSEC_PER_SEC 1000000000ULL
30c5fffcb2SJohn Stultz
31c5fffcb2SJohn Stultz #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
32c5fffcb2SJohn Stultz
33c5fffcb2SJohn Stultz
34c5fffcb2SJohn Stultz #define CLOCK_REALTIME 0
35c5fffcb2SJohn Stultz #define CLOCK_MONOTONIC 1
36c5fffcb2SJohn Stultz #define CLOCK_PROCESS_CPUTIME_ID 2
37c5fffcb2SJohn Stultz #define CLOCK_THREAD_CPUTIME_ID 3
38c5fffcb2SJohn Stultz #define CLOCK_MONOTONIC_RAW 4
39c5fffcb2SJohn Stultz #define CLOCK_REALTIME_COARSE 5
40c5fffcb2SJohn Stultz #define CLOCK_MONOTONIC_COARSE 6
41c5fffcb2SJohn Stultz #define CLOCK_BOOTTIME 7
42c5fffcb2SJohn Stultz #define CLOCK_REALTIME_ALARM 8
43c5fffcb2SJohn Stultz #define CLOCK_BOOTTIME_ALARM 9
44c5fffcb2SJohn Stultz #define CLOCK_HWSPECIFIC 10
45c5fffcb2SJohn Stultz #define CLOCK_TAI 11
46c5fffcb2SJohn Stultz #define NR_CLOCKIDS 12
47c5fffcb2SJohn Stultz
48c5fffcb2SJohn Stultz #define UNSUPPORTED 0xf00f
49c5fffcb2SJohn Stultz
clockstring(int clockid)50c5fffcb2SJohn Stultz char *clockstring(int clockid)
51c5fffcb2SJohn Stultz {
52c5fffcb2SJohn Stultz switch (clockid) {
53c5fffcb2SJohn Stultz case CLOCK_REALTIME:
54c5fffcb2SJohn Stultz return "CLOCK_REALTIME";
55c5fffcb2SJohn Stultz case CLOCK_MONOTONIC:
56c5fffcb2SJohn Stultz return "CLOCK_MONOTONIC";
57c5fffcb2SJohn Stultz case CLOCK_PROCESS_CPUTIME_ID:
58c5fffcb2SJohn Stultz return "CLOCK_PROCESS_CPUTIME_ID";
59c5fffcb2SJohn Stultz case CLOCK_THREAD_CPUTIME_ID:
60c5fffcb2SJohn Stultz return "CLOCK_THREAD_CPUTIME_ID";
61c5fffcb2SJohn Stultz case CLOCK_MONOTONIC_RAW:
62c5fffcb2SJohn Stultz return "CLOCK_MONOTONIC_RAW";
63c5fffcb2SJohn Stultz case CLOCK_REALTIME_COARSE:
64c5fffcb2SJohn Stultz return "CLOCK_REALTIME_COARSE";
65c5fffcb2SJohn Stultz case CLOCK_MONOTONIC_COARSE:
66c5fffcb2SJohn Stultz return "CLOCK_MONOTONIC_COARSE";
67c5fffcb2SJohn Stultz case CLOCK_BOOTTIME:
68c5fffcb2SJohn Stultz return "CLOCK_BOOTTIME";
69c5fffcb2SJohn Stultz case CLOCK_REALTIME_ALARM:
70c5fffcb2SJohn Stultz return "CLOCK_REALTIME_ALARM";
71c5fffcb2SJohn Stultz case CLOCK_BOOTTIME_ALARM:
72c5fffcb2SJohn Stultz return "CLOCK_BOOTTIME_ALARM";
73c5fffcb2SJohn Stultz case CLOCK_TAI:
74c5fffcb2SJohn Stultz return "CLOCK_TAI";
75c5fffcb2SJohn Stultz };
76c5fffcb2SJohn Stultz return "UNKNOWN_CLOCKID";
77c5fffcb2SJohn Stultz }
78c5fffcb2SJohn Stultz
timespec_add(struct timespec ts,unsigned long long ns)79c5fffcb2SJohn Stultz struct timespec timespec_add(struct timespec ts, unsigned long long ns)
80c5fffcb2SJohn Stultz {
81c5fffcb2SJohn Stultz ts.tv_nsec += ns;
82c5fffcb2SJohn Stultz while (ts.tv_nsec >= NSEC_PER_SEC) {
83c5fffcb2SJohn Stultz ts.tv_nsec -= NSEC_PER_SEC;
84c5fffcb2SJohn Stultz ts.tv_sec++;
85c5fffcb2SJohn Stultz }
86c5fffcb2SJohn Stultz return ts;
87c5fffcb2SJohn Stultz }
88c5fffcb2SJohn Stultz
89c5fffcb2SJohn Stultz
timespec_sub(struct timespec a,struct timespec b)90c5fffcb2SJohn Stultz long long timespec_sub(struct timespec a, struct timespec b)
91c5fffcb2SJohn Stultz {
92c5fffcb2SJohn Stultz long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
93c5fffcb2SJohn Stultz
94c5fffcb2SJohn Stultz ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
95c5fffcb2SJohn Stultz return ret;
96c5fffcb2SJohn Stultz }
97c5fffcb2SJohn Stultz
nanosleep_lat_test(int clockid,long long ns)98c5fffcb2SJohn Stultz int nanosleep_lat_test(int clockid, long long ns)
99c5fffcb2SJohn Stultz {
100c5fffcb2SJohn Stultz struct timespec start, end, target;
101c5fffcb2SJohn Stultz long long latency = 0;
102c5fffcb2SJohn Stultz int i, count;
103c5fffcb2SJohn Stultz
104c5fffcb2SJohn Stultz target.tv_sec = ns/NSEC_PER_SEC;
105c5fffcb2SJohn Stultz target.tv_nsec = ns%NSEC_PER_SEC;
106c5fffcb2SJohn Stultz
107c5fffcb2SJohn Stultz if (clock_gettime(clockid, &start))
108c5fffcb2SJohn Stultz return UNSUPPORTED;
109c5fffcb2SJohn Stultz if (clock_nanosleep(clockid, 0, &target, NULL))
110c5fffcb2SJohn Stultz return UNSUPPORTED;
111c5fffcb2SJohn Stultz
112c5fffcb2SJohn Stultz count = 10;
113c5fffcb2SJohn Stultz
114c5fffcb2SJohn Stultz /* First check relative latency */
115c5fffcb2SJohn Stultz clock_gettime(clockid, &start);
116c5fffcb2SJohn Stultz for (i = 0; i < count; i++)
117c5fffcb2SJohn Stultz clock_nanosleep(clockid, 0, &target, NULL);
118c5fffcb2SJohn Stultz clock_gettime(clockid, &end);
119c5fffcb2SJohn Stultz
120c5fffcb2SJohn Stultz if (((timespec_sub(start, end)/count)-ns) > UNRESONABLE_LATENCY) {
121c5fffcb2SJohn Stultz printf("Large rel latency: %lld ns :", (timespec_sub(start, end)/count)-ns);
122c5fffcb2SJohn Stultz return -1;
123c5fffcb2SJohn Stultz }
124c5fffcb2SJohn Stultz
125c5fffcb2SJohn Stultz /* Next check absolute latency */
126c5fffcb2SJohn Stultz for (i = 0; i < count; i++) {
127c5fffcb2SJohn Stultz clock_gettime(clockid, &start);
128c5fffcb2SJohn Stultz target = timespec_add(start, ns);
129c5fffcb2SJohn Stultz clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL);
130c5fffcb2SJohn Stultz clock_gettime(clockid, &end);
131c5fffcb2SJohn Stultz latency += timespec_sub(target, end);
132c5fffcb2SJohn Stultz }
133c5fffcb2SJohn Stultz
134c5fffcb2SJohn Stultz if (latency/count > UNRESONABLE_LATENCY) {
135c5fffcb2SJohn Stultz printf("Large abs latency: %lld ns :", latency/count);
136c5fffcb2SJohn Stultz return -1;
137c5fffcb2SJohn Stultz }
138c5fffcb2SJohn Stultz
139c5fffcb2SJohn Stultz return 0;
140c5fffcb2SJohn Stultz }
141c5fffcb2SJohn Stultz
142c5fffcb2SJohn Stultz
143c5fffcb2SJohn Stultz
main(int argc,char ** argv)144c5fffcb2SJohn Stultz int main(int argc, char **argv)
145c5fffcb2SJohn Stultz {
146c5fffcb2SJohn Stultz long long length;
147c5fffcb2SJohn Stultz int clockid, ret;
148c5fffcb2SJohn Stultz
149c5fffcb2SJohn Stultz for (clockid = CLOCK_REALTIME; clockid < NR_CLOCKIDS; clockid++) {
150c5fffcb2SJohn Stultz
151c5fffcb2SJohn Stultz /* Skip cputime clockids since nanosleep won't increment cputime */
152c5fffcb2SJohn Stultz if (clockid == CLOCK_PROCESS_CPUTIME_ID ||
153c5fffcb2SJohn Stultz clockid == CLOCK_THREAD_CPUTIME_ID ||
154c5fffcb2SJohn Stultz clockid == CLOCK_HWSPECIFIC)
155c5fffcb2SJohn Stultz continue;
156c5fffcb2SJohn Stultz
157c5fffcb2SJohn Stultz printf("nsleep latency %-26s ", clockstring(clockid));
158fe483192SKees Cook fflush(stdout);
159c5fffcb2SJohn Stultz
160c5fffcb2SJohn Stultz length = 10;
161c5fffcb2SJohn Stultz while (length <= (NSEC_PER_SEC * 10)) {
162c5fffcb2SJohn Stultz ret = nanosleep_lat_test(clockid, length);
163c5fffcb2SJohn Stultz if (ret)
164c5fffcb2SJohn Stultz break;
165c5fffcb2SJohn Stultz length *= 100;
166c5fffcb2SJohn Stultz
167c5fffcb2SJohn Stultz }
168c5fffcb2SJohn Stultz
169c5fffcb2SJohn Stultz if (ret == UNSUPPORTED) {
170c5fffcb2SJohn Stultz printf("[UNSUPPORTED]\n");
171c5fffcb2SJohn Stultz continue;
172c5fffcb2SJohn Stultz }
173c5fffcb2SJohn Stultz if (ret < 0) {
174c5fffcb2SJohn Stultz printf("[FAILED]\n");
175c5fffcb2SJohn Stultz return ksft_exit_fail();
176c5fffcb2SJohn Stultz }
177c5fffcb2SJohn Stultz printf("[OK]\n");
178c5fffcb2SJohn Stultz }
179c5fffcb2SJohn Stultz return ksft_exit_pass();
180c5fffcb2SJohn Stultz }
181