projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 274d631e JS |
1 | /* Measure mqueue timeout latency |
| 2 | * by: john stultz (john.stultz@linaro.org) | |
| 3 | * (C) Copyright Linaro 2013 | |
| 4 | * | |
| 5 | * Inspired with permission from example test by: | |
| 6 | * Romain Francoise <romain@orebokech.com> | |
| 7 | * Licensed under the GPLv2 | |
| 8 | * | |
| 9 | * To build: | |
| 10 | * $ gcc mqueue-lat.c -o mqueue-lat -lrt | |
| 11 | * | |
| 12 | * This program is free software: you can redistribute it and/or modify | |
| 13 | * it under the terms of the GNU General Public License as published by | |
| 14 | * the Free Software Foundation, either version 2 of the License, or | |
| 15 | * (at your option) any later version. | |
| 16 | * | |
| 17 | * This program is distributed in the hope that it will be useful, | |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 20 | * GNU General Public License for more details. | |
| 21 | */ | |
| 22 | ||
| 23 | #include <stdio.h> | |
| 24 | #include <stdlib.h> | |
| 25 | #include <time.h> | |
| 26 | #include <sys/time.h> | |
| 27 | #include <sys/timex.h> | |
| 28 | #include <string.h> | |
| 29 | #include <signal.h> | |
| 30 | #include <errno.h> | |
| 31 | #include <mqueue.h> | |
| 32 | #ifdef KTEST | |
| 33 | #include "../kselftest.h" | |
| 34 | #else | |
| 35 | static inline int ksft_exit_pass(void) | |
| 36 | { | |
| 37 | exit(0); | |
| 38 | } | |
| 39 | static inline int ksft_exit_fail(void) | |
| 40 | { | |
| 41 | exit(1); | |
| 42 | } | |
| 43 | #endif | |
| 44 | ||
| 45 | #define NSEC_PER_SEC 1000000000ULL | |
| 46 | ||
| 47 | #define TARGET_TIMEOUT 100000000 /* 100ms in nanoseconds */ | |
| 48 | #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */ | |
| 49 | ||
| 50 | ||
| 51 | long long timespec_sub(struct timespec a, struct timespec b) | |
| 52 | { | |
| 53 | long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec; | |
| 54 | ||
| 55 | ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec; | |
| 56 | return ret; | |
| 57 | } | |
| 58 | ||
| 59 | struct timespec timespec_add(struct timespec ts, unsigned long long ns) | |
| 60 | { | |
| 61 | ts.tv_nsec += ns; | |
| 62 | while (ts.tv_nsec >= NSEC_PER_SEC) { | |
| 63 | ts.tv_nsec -= NSEC_PER_SEC; | |
| 64 | ts.tv_sec++; | |
| 65 | } | |
| 66 | return ts; | |
| 67 | } | |
| 68 | ||
| 69 | int mqueue_lat_test(void) | |
| 70 | { | |
| 71 | ||
| 72 | mqd_t q; | |
| 73 | struct mq_attr attr; | |
| 74 | struct timespec start, end, now, target; | |
| 75 | int i, count, ret; | |
| 76 | ||
| 77 | q = mq_open("/foo", O_CREAT | O_RDONLY, 0666, NULL); | |
| 78 | if (q < 0) { | |
| 79 | perror("mq_open"); | |
| 80 | return -1; | |
| 81 | } | |
| 82 | mq_getattr(q, &attr); | |
| 83 | ||
| 84 | ||
| 85 | count = 100; | |
| 86 | clock_gettime(CLOCK_MONOTONIC, &start); | |
| 87 | ||
| 88 | for (i = 0; i < count; i++) { | |
| 89 | char buf[attr.mq_msgsize]; | |
| 90 | ||
| 91 | clock_gettime(CLOCK_REALTIME, &now); | |
| 92 | target = now; | |
| 93 | target = timespec_add(now, TARGET_TIMEOUT); /* 100ms */ | |
| 94 | ||
| 95 | ret = mq_timedreceive(q, buf, sizeof(buf), NULL, &target); | |
| 96 | if (ret < 0 && errno != ETIMEDOUT) { | |
| 97 | perror("mq_timedreceive"); | |
| 98 | return -1; | |
| 99 | } | |
| 100 | } | |
| 101 | clock_gettime(CLOCK_MONOTONIC, &end); | |
| 102 | ||
| 103 | mq_close(q); | |
| 104 | ||
| 105 | if ((timespec_sub(start, end)/count) > TARGET_TIMEOUT + UNRESONABLE_LATENCY) | |
| 106 | return -1; | |
| 107 | ||
| 108 | return 0; | |
| 109 | } | |
| 110 | ||
| 111 | int main(int argc, char **argv) | |
| 112 | { | |
| 113 | int ret; | |
| 114 | ||
| 115 | printf("Mqueue latency : "); | |
| 116 | ||
| 117 | ret = mqueue_lat_test(); | |
| 118 | if (ret < 0) { | |
| 119 | printf("[FAILED]\n"); | |
| 120 | return ksft_exit_fail(); | |
| 121 | } | |
| 122 | printf("[OK]\n"); | |
| 123 | return ksft_exit_pass(); | |
| 124 | } |