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Release 4.18 tools/testing/selftests/timers/set-timer-lat.c

/* set_timer latency test
 *              John Stultz (john.stultz@linaro.org)
 *              (C) Copyright Linaro 2014
 *              Licensed under the GPLv2
 *
 *   This test makes sure the set_timer api is correct
 *
 *  To build:
 *      $ gcc set-timer-lat.c -o set-timer-lat -lrt
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 */


#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <signal.h>
#include <stdlib.h>
#include <pthread.h>
#include "../kselftest.h"


#define CLOCK_REALTIME			0

#define CLOCK_MONOTONIC			1

#define CLOCK_PROCESS_CPUTIME_ID	2

#define CLOCK_THREAD_CPUTIME_ID		3

#define CLOCK_MONOTONIC_RAW		4

#define CLOCK_REALTIME_COARSE		5

#define CLOCK_MONOTONIC_COARSE		6

#define CLOCK_BOOTTIME			7

#define CLOCK_REALTIME_ALARM		8

#define CLOCK_BOOTTIME_ALARM		9

#define CLOCK_HWSPECIFIC		10

#define CLOCK_TAI			11

#define NR_CLOCKIDS			12



#define NSEC_PER_SEC 1000000000ULL

#define UNRESONABLE_LATENCY 40000000 
/* 40ms in nanosecs */


#define TIMER_SECS 1

int alarmcount;

int clock_id;

struct timespec start_time;

long long max_latency_ns;

int timer_fired_early;


char *clockstring(int clockid) { switch (clockid) { case CLOCK_REALTIME: return "CLOCK_REALTIME"; case CLOCK_MONOTONIC: return "CLOCK_MONOTONIC"; case CLOCK_PROCESS_CPUTIME_ID: return "CLOCK_PROCESS_CPUTIME_ID"; case CLOCK_THREAD_CPUTIME_ID: return "CLOCK_THREAD_CPUTIME_ID"; case CLOCK_MONOTONIC_RAW: return "CLOCK_MONOTONIC_RAW"; case CLOCK_REALTIME_COARSE: return "CLOCK_REALTIME_COARSE"; case CLOCK_MONOTONIC_COARSE: return "CLOCK_MONOTONIC_COARSE"; case CLOCK_BOOTTIME: return "CLOCK_BOOTTIME"; case CLOCK_REALTIME_ALARM: return "CLOCK_REALTIME_ALARM"; case CLOCK_BOOTTIME_ALARM: return "CLOCK_BOOTTIME_ALARM"; case CLOCK_TAI: return "CLOCK_TAI"; }; return "UNKNOWN_CLOCKID"; }

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John Stultz85100.00%1100.00%
Total85100.00%1100.00%


long long timespec_sub(struct timespec a, struct timespec b) { long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec; ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec; return ret; }

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John Stultz43100.00%1100.00%
Total43100.00%1100.00%


void sigalarm(int signo) { long long delta_ns; struct timespec ts; clock_gettime(clock_id, &ts); alarmcount++; delta_ns = timespec_sub(start_time, ts); delta_ns -= NSEC_PER_SEC * TIMER_SECS * alarmcount; if (delta_ns < 0) timer_fired_early = 1; if (delta_ns > max_latency_ns) max_latency_ns = delta_ns; }

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John Stultz6195.31%150.00%
Greg Hackmann34.69%150.00%
Total64100.00%2100.00%


void describe_timer(int flags, int interval) { printf("%-22s %s %s ", clockstring(clock_id), flags ? "ABSTIME":"RELTIME", interval ? "PERIODIC":"ONE-SHOT"); }

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Greg Hackmann33100.00%2100.00%
Total33100.00%2100.00%


int setup_timer(int clock_id, int flags, int interval, timer_t *tm1) { struct sigevent se; struct itimerspec its1, its2; int err; /* Set up timer: */ memset(&se, 0, sizeof(se)); se.sigev_notify = SIGEV_SIGNAL; se.sigev_signo = SIGRTMAX; se.sigev_value.sival_int = 0; max_latency_ns = 0; alarmcount = 0; timer_fired_early = 0; err = timer_create(clock_id, &se, tm1); if (err) { if ((clock_id == CLOCK_REALTIME_ALARM) || (clock_id == CLOCK_BOOTTIME_ALARM)) { printf("%-22s %s missing CAP_WAKE_ALARM? : [UNSUPPORTED]\n", clockstring(clock_id), flags ? "ABSTIME":"RELTIME"); /* Indicate timer isn't set, so caller doesn't wait */ return 1; } printf("%s - timer_create() failed\n", clockstring(clock_id)); return -1; } clock_gettime(clock_id, &start_time); if (flags) { its1.it_value = start_time; its1.it_value.tv_sec += TIMER_SECS; } else { its1.it_value.tv_sec = TIMER_SECS; its1.it_value.tv_nsec = 0; } its1.it_interval.tv_sec = interval; its1.it_interval.tv_nsec = 0; err = timer_settime(*tm1, flags, &its1, &its2); if (err) { printf("%s - timer_settime() failed\n", clockstring(clock_id)); return -1; } return 0; }

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PersonTokensPropCommitsCommitProp
John Stultz22791.90%240.00%
Greg Hackmann187.29%240.00%
Shuah Khan20.81%120.00%
Total247100.00%5100.00%


int check_timer_latency(int flags, int interval) { int err = 0; describe_timer(flags, interval); printf("timer fired early: %7d : ", timer_fired_early); if (!timer_fired_early) { printf("[OK]\n"); } else { printf("[FAILED]\n"); err = -1; } describe_timer(flags, interval); printf("max latency: %10lld ns : ", max_latency_ns); if (max_latency_ns < UNRESONABLE_LATENCY) { printf("[OK]\n"); } else { printf("[FAILED]\n"); err = -1; } return err; }

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PersonTokensPropCommitsCommitProp
Greg Hackmann6667.35%266.67%
John Stultz3232.65%133.33%
Total98100.00%3100.00%


int check_alarmcount(int flags, int interval) { describe_timer(flags, interval); printf("count: %19d : ", alarmcount); if (alarmcount == 1) { printf("[OK]\n"); return 0; } printf("[FAILED]\n"); return -1; }

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Greg Hackmann50100.00%1100.00%
Total50100.00%1100.00%


int do_timer(int clock_id, int flags) { timer_t tm1; const int interval = TIMER_SECS; int err; err = setup_timer(clock_id, flags, interval, &tm1); /* Unsupported case - return 0 to not fail the test */ if (err) return err == 1 ? 0 : err; while (alarmcount < 5) sleep(1); timer_delete(tm1); return check_timer_latency(flags, interval); }

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Greg Hackmann6890.67%150.00%
Shuah Khan79.33%150.00%
Total75100.00%2100.00%


int do_timer_oneshot(int clock_id, int flags) { timer_t tm1; const int interval = 0; struct timeval timeout; int err; err = setup_timer(clock_id, flags, interval, &tm1); /* Unsupported case - return 0 to not fail the test */ if (err) return err == 1 ? 0 : err; memset(&timeout, 0, sizeof(timeout)); timeout.tv_sec = 5; do { err = select(0, NULL, NULL, NULL, &timeout); } while (err == -1 && errno == EINTR); timer_delete(tm1); err = check_timer_latency(flags, interval); err |= check_alarmcount(flags, interval); return err; }

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Greg Hackmann12293.13%133.33%
Shuah Khan96.87%266.67%
Total131100.00%3100.00%


int main(void) { struct sigaction act; int signum = SIGRTMAX; int ret = 0; /* Set up signal handler: */ sigfillset(&act.sa_mask); act.sa_flags = 0; act.sa_handler = sigalarm; sigaction(signum, &act, NULL); printf("Setting timers for every %i seconds\n", TIMER_SECS); for (clock_id = 0; clock_id < NR_CLOCKIDS; clock_id++) { if ((clock_id == CLOCK_PROCESS_CPUTIME_ID) || (clock_id == CLOCK_THREAD_CPUTIME_ID) || (clock_id == CLOCK_MONOTONIC_RAW) || (clock_id == CLOCK_REALTIME_COARSE) || (clock_id == CLOCK_MONOTONIC_COARSE) || (clock_id == CLOCK_HWSPECIFIC)) continue; ret |= do_timer(clock_id, TIMER_ABSTIME); ret |= do_timer(clock_id, 0); ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME); ret |= do_timer_oneshot(clock_id, 0); } if (ret) return ksft_exit_fail(); return ksft_exit_pass(); }

Contributors

PersonTokensPropCommitsCommitProp
John Stultz14388.82%150.00%
Greg Hackmann1811.18%150.00%
Total161100.00%2100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
John Stultz69563.35%342.86%
Greg Hackmann38435.00%228.57%
Shuah Khan181.64%228.57%
Total1097100.00%7100.00%
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