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