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author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-06-28 00:06:43 +0000 |
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committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-07-03 16:20:03 +0200 |
commit | 0bc4b0cf15708fca04095232c4e448634e94d029 (patch) | |
tree | 9c6d6e455c20b7fa19adfc22928dd5e5f839a12a /tools/testing/selftests | |
parent | 2473f3e7a97ce8bc0fe7596cdb361b21221418eb (diff) | |
download | linux-stable-0bc4b0cf15708fca04095232c4e448634e94d029.tar.gz linux-stable-0bc4b0cf15708fca04095232c4e448634e94d029.tar.bz2 linux-stable-0bc4b0cf15708fca04095232c4e448634e94d029.zip |
selftests: add basic posix timers selftests
Add some initial basic tests on a few posix timers interface such as
setitimer() and timer_settime().
These simply check that expiration happens in a reasonable timeframe after
expected elapsed clock time (user time, user + system time, real time,
...).
This is helpful for finding basic breakages while hacking
on this subsystem.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools/testing/selftests')
-rw-r--r-- | tools/testing/selftests/Makefile | 1 | ||||
-rw-r--r-- | tools/testing/selftests/timers/Makefile | 8 | ||||
-rw-r--r-- | tools/testing/selftests/timers/posix_timers.c | 221 |
3 files changed, 230 insertions, 0 deletions
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 0a63658065f0..4cb14cae3791 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -6,6 +6,7 @@ TARGETS += memory-hotplug TARGETS += mqueue TARGETS += net TARGETS += ptrace +TARGETS += timers TARGETS += vm all: diff --git a/tools/testing/selftests/timers/Makefile b/tools/testing/selftests/timers/Makefile new file mode 100644 index 000000000000..eb2859f4ad21 --- /dev/null +++ b/tools/testing/selftests/timers/Makefile @@ -0,0 +1,8 @@ +all: + gcc posix_timers.c -o posix_timers -lrt + +run_tests: all + ./posix_timers + +clean: + rm -f ./posix_timers diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c new file mode 100644 index 000000000000..4fa655d68a81 --- /dev/null +++ b/tools/testing/selftests/timers/posix_timers.c @@ -0,0 +1,221 @@ +/* + * Copyright (C) 2013 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com> + * + * Licensed under the terms of the GNU GPL License version 2 + * + * Selftests for a few posix timers interface. + * + * Kernel loop code stolen from Steven Rostedt <srostedt@redhat.com> + */ + +#include <sys/time.h> +#include <stdio.h> +#include <signal.h> +#include <unistd.h> +#include <time.h> +#include <pthread.h> + +#define DELAY 2 +#define USECS_PER_SEC 1000000 + +static volatile int done; + +/* Busy loop in userspace to elapse ITIMER_VIRTUAL */ +static void user_loop(void) +{ + while (!done); +} + +/* + * Try to spend as much time as possible in kernelspace + * to elapse ITIMER_PROF. + */ +static void kernel_loop(void) +{ + void *addr = sbrk(0); + + while (!done) { + brk(addr + 4096); + brk(addr); + } +} + +/* + * Sleep until ITIMER_REAL expiration. + */ +static void idle_loop(void) +{ + pause(); +} + +static void sig_handler(int nr) +{ + done = 1; +} + +/* + * Check the expected timer expiration matches the GTOD elapsed delta since + * we armed the timer. Keep a 0.5 sec error margin due to various jitter. + */ +static int check_diff(struct timeval start, struct timeval end) +{ + long long diff; + + diff = end.tv_usec - start.tv_usec; + diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC; + + if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) { + printf("Diff too high: %lld..", diff); + return -1; + } + + return 0; +} + +static int check_itimer(int which) +{ + int err; + struct timeval start, end; + struct itimerval val = { + .it_value.tv_sec = DELAY, + }; + + printf("Check itimer "); + + if (which == ITIMER_VIRTUAL) + printf("virtual... "); + else if (which == ITIMER_PROF) + printf("prof... "); + else if (which == ITIMER_REAL) + printf("real... "); + + fflush(stdout); + + done = 0; + + if (which == ITIMER_VIRTUAL) + signal(SIGVTALRM, sig_handler); + else if (which == ITIMER_PROF) + signal(SIGPROF, sig_handler); + else if (which == ITIMER_REAL) + signal(SIGALRM, sig_handler); + + err = gettimeofday(&start, NULL); + if (err < 0) { + perror("Can't call gettimeofday()\n"); + return -1; + } + + err = setitimer(which, &val, NULL); + if (err < 0) { + perror("Can't set timer\n"); + return -1; + } + + if (which == ITIMER_VIRTUAL) + user_loop(); + else if (which == ITIMER_PROF) + kernel_loop(); + else if (which == ITIMER_REAL) + idle_loop(); + + gettimeofday(&end, NULL); + if (err < 0) { + perror("Can't call gettimeofday()\n"); + return -1; + } + + if (!check_diff(start, end)) + printf("[OK]\n"); + else + printf("[FAIL]\n"); + + return 0; +} + +static int check_timer_create(int which) +{ + int err; + timer_t id; + struct timeval start, end; + struct itimerspec val = { + .it_value.tv_sec = DELAY, + }; + + printf("Check timer_create() "); + if (which == CLOCK_THREAD_CPUTIME_ID) { + printf("per thread... "); + } else if (which == CLOCK_PROCESS_CPUTIME_ID) { + printf("per process... "); + } + fflush(stdout); + + done = 0; + timer_create(which, NULL, &id); + if (err < 0) { + perror("Can't create timer\n"); + return -1; + } + signal(SIGALRM, sig_handler); + + err = gettimeofday(&start, NULL); + if (err < 0) { + perror("Can't call gettimeofday()\n"); + return -1; + } + + err = timer_settime(id, 0, &val, NULL); + if (err < 0) { + perror("Can't set timer\n"); + return -1; + } + + user_loop(); + + gettimeofday(&end, NULL); + if (err < 0) { + perror("Can't call gettimeofday()\n"); + return -1; + } + + if (!check_diff(start, end)) + printf("[OK]\n"); + else + printf("[FAIL]\n"); + + return 0; +} + +int main(int argc, char **argv) +{ + int err; + + printf("Testing posix timers. False negative may happen on CPU execution \n"); + printf("based timers if other threads run on the CPU...\n"); + + if (check_itimer(ITIMER_VIRTUAL) < 0) + return -1; + + if (check_itimer(ITIMER_PROF) < 0) + return -1; + + if (check_itimer(ITIMER_REAL) < 0) + return -1; + + if (check_timer_create(CLOCK_THREAD_CPUTIME_ID) < 0) + return -1; + + /* + * It's unfortunately hard to reliably test a timer expiration + * on parallel multithread cputime. We could arm it to expire + * on DELAY * nr_threads, with nr_threads busy looping, then wait + * the normal DELAY since the time is elapsing nr_threads faster. + * But for that we need to ensure we have real physical free CPUs + * to ensure true parallelism. So test only one thread until we + * find a better solution. + */ + if (check_timer_create(CLOCK_PROCESS_CPUTIME_ID) < 0) + return -1; + + return 0; +} |