selftests/timers: Add set-timer-lat test from timetest suite

Add my set-timer-lat test from the timetest suite. This
test checks the latency from set_timer and reports if
any are unreasonable (>40ms).

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

2 files changed, 213 insertions, 1 deletions

diff --git a/tools/testing/selftests/timers/Makefile b/tools/testing/selftests/timers/Makefile
index 088a791a44cb..f69bdce0b8f3 100644
--- a/tools/testing/selftests/timers/Makefile
+++ b/tools/testing/selftests/timers/Makefile
@@ -2,7 +2,8 @@ CC = $(CROSS_COMPILE)gcc
 BUILD_FLAGS = -DKTEST
 CFLAGS += -O3 -Wl,-no-as-needed -Wall $(BUILD_FLAGS)
 LDFLAGS += -lrt -lpthread
-bins = posix_timers nanosleep inconsistency-check nsleep-lat raw_skew
+bins = posix_timers nanosleep inconsistency-check nsleep-lat raw_skew \
+        set-timer-lat
 
 all: ${bins}
 
@@ -10,7 +11,9 @@ run_tests: all
         ./posix_timers
         ./nanosleep
         ./nsleep-lat
+        ./set-timer-lat
         ./inconsistency-check
         ./raw_skew
+
 clean:
         rm -f ${bins}
diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c
new file mode 100644
index 000000000000..3ea2effbcc22
--- /dev/null
+++ b/tools/testing/selftests/timers/set-timer-lat.c
@@ -0,0 +1,209 @@
+/* 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 <stdio.h>
+#include <unistd.h>
+#include <time.h>
+#include <string.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <pthread.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+        exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+        exit(1);
+}
+#endif
+
+#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 3
+int alarmcount;
+int clock_id;
+struct timespec start_time;
+long long max_latency_ns;
+
+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";
+}
+
+
+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;
+}
+
+
+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)
+                printf("%s timer fired early: FAIL\n", clockstring(clock_id));
+
+        if (delta_ns > max_latency_ns)
+                max_latency_ns = delta_ns;
+}
+
+int do_timer(int clock_id, int flags)
+{
+        struct sigevent se;
+        timer_t tm1;
+        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;
+
+        err = timer_create(clock_id, &se, &tm1);
+        if (err) {
+                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 = TIMER_SECS;
+        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;
+        }
+
+        while (alarmcount < 5)
+                sleep(1);
+
+        printf("%-22s %s max latency: %10lld ns : ",
+                        clockstring(clock_id),
+                        flags ? "ABSTIME":"RELTIME",
+                        max_latency_ns);
+
+        timer_delete(tm1);
+        if (max_latency_ns < UNRESONABLE_LATENCY) {
+                printf("[OK]\n");
+                return 0;
+        }
+        printf("[FAILED]\n");
+        return -1;
+}
+
+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);
+        }
+        if (ret)
+                return ksft_exit_fail();
+        return ksft_exit_pass();
+}