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114 lines
2.6 KiB
114 lines
2.6 KiB
/* Measure mqueue timeout latency |
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* by: john stultz ([email protected]) |
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* (C) Copyright Linaro 2013 |
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* |
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* Inspired with permission from example test by: |
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* Romain Francoise <[email protected]> |
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* Licensed under the GPLv2 |
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* |
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* To build: |
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* $ gcc mqueue-lat.c -o mqueue-lat -lrt |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation, either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <time.h> |
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#include <sys/time.h> |
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#include <sys/timex.h> |
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#include <string.h> |
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#include <signal.h> |
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#include <errno.h> |
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#include <mqueue.h> |
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#include "../kselftest.h" |
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#define NSEC_PER_SEC 1000000000ULL |
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#define TARGET_TIMEOUT 100000000 /* 100ms in nanoseconds */ |
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#define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */ |
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long long timespec_sub(struct timespec a, struct timespec b) |
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{ |
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long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec; |
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ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec; |
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return ret; |
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} |
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struct timespec timespec_add(struct timespec ts, unsigned long long ns) |
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{ |
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ts.tv_nsec += ns; |
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while (ts.tv_nsec >= NSEC_PER_SEC) { |
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ts.tv_nsec -= NSEC_PER_SEC; |
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ts.tv_sec++; |
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} |
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return ts; |
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} |
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int mqueue_lat_test(void) |
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{ |
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mqd_t q; |
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struct mq_attr attr; |
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struct timespec start, end, now, target; |
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int i, count, ret; |
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q = mq_open("/foo", O_CREAT | O_RDONLY, 0666, NULL); |
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if (q < 0) { |
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perror("mq_open"); |
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return -1; |
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} |
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mq_getattr(q, &attr); |
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count = 100; |
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clock_gettime(CLOCK_MONOTONIC, &start); |
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for (i = 0; i < count; i++) { |
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char buf[attr.mq_msgsize]; |
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clock_gettime(CLOCK_REALTIME, &now); |
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target = now; |
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target = timespec_add(now, TARGET_TIMEOUT); /* 100ms */ |
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ret = mq_timedreceive(q, buf, sizeof(buf), NULL, &target); |
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if (ret < 0 && errno != ETIMEDOUT) { |
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perror("mq_timedreceive"); |
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return -1; |
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} |
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} |
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clock_gettime(CLOCK_MONOTONIC, &end); |
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mq_close(q); |
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if ((timespec_sub(start, end)/count) > TARGET_TIMEOUT + UNRESONABLE_LATENCY) |
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return -1; |
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return 0; |
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} |
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int main(int argc, char **argv) |
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{ |
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int ret; |
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printf("Mqueue latency : "); |
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fflush(stdout); |
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ret = mqueue_lat_test(); |
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if (ret < 0) { |
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printf("[FAILED]\n"); |
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return ksft_exit_fail(); |
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} |
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printf("[OK]\n"); |
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return ksft_exit_pass(); |
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}
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