~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/tools/testing/selftests/timers/nsleep-lat.c

Version: ~ [ linux-5.1-rc5 ] ~ [ linux-5.0.7 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.34 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.111 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.168 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.178 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.138 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.65 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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>
 27 #include "../kselftest.h"
 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));
158 
159                 length = 10;
160                 while (length <= (NSEC_PER_SEC * 10)) {
161                         ret = nanosleep_lat_test(clockid, length);
162                         if (ret)
163                                 break;
164                         length *= 100;
165 
166                 }
167 
168                 if (ret == UNSUPPORTED) {
169                         printf("[UNSUPPORTED]\n");
170                         continue;
171                 }
172                 if (ret < 0) {
173                         printf("[FAILED]\n");
174                         return ksft_exit_fail();
175                 }
176                 printf("[OK]\n");
177         }
178         return ksft_exit_pass();
179 }
180 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp