Recently an issue was reported that was difficult to detect except
by tweaking the adjtimex tick value, and noticing how quickly the
adjustment took to be made:
https://lkml.org/lkml/2015/9/1/488
Thus this patch introduces a new test which manipulates the adjtimex
tick value and validates the results are what we expect.
Cc: Nuno Gonçalves <nuno...@gmail.com>
Cc: Miroslav Lichvar <mlich...@redhat.com>
Cc: Prarit Bhargava <pra...@redhat.com>
Cc: Richard Cochran <richardcoch...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Shuah Khan <shua...@osg.samsung.com>
Signed-off-by: John Stultz <john.stu...@linaro.org>
---
tools/testing/selftests/timers/Makefile | 3 +-
tools/testing/selftests/timers/adjtick.c | 186 +++++++++++++++++++++++++++++++
2 files changed, 188 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/timers/adjtick.c
diff --git a/tools/testing/selftests/timers/Makefile
b/tools/testing/selftests/timers/Makefile
index 89a3f44..4a1be1b 100644
--- a/tools/testing/selftests/timers/Makefile
+++ b/tools/testing/selftests/timers/Makefile
@@ -8,7 +8,7 @@ LDFLAGS += -lrt -lpthread
TEST_PROGS = posix_timers nanosleep nsleep-lat set-timer-lat mqueue-lat \
inconsistency-check raw_skew threadtest rtctest
-TEST_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex change_skew \
+TEST_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex adjtick change_skew \
skew_consistency clocksource-switch leap-a-day \
leapcrash set-tai set-2038
@@ -24,6 +24,7 @@ include ../lib.mk
run_destructive_tests: run_tests
./alarmtimer-suspend
./valid-adjtimex
+ ./adjtick
./change_skew
./skew_consistency
./clocksource-switch
diff --git a/tools/testing/selftests/timers/adjtick.c
b/tools/testing/selftests/timers/adjtick.c
new file mode 100644
index 0000000..b13c7fc
--- /dev/null
+++ b/tools/testing/selftests/timers/adjtick.c
@@ -0,0 +1,186 @@
+/* adjtimex() tick adjustment test
+ * by: John Stultz <john.stu...@linaro.org>
+ * (C) Copyright Linaro Limited 2015
+ * Licensed under the GPLv2
+ *
+ * To build:
+ * $ gcc adjtick.c -o adjtick -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 <stdlib.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <time.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_MONOTONIC_RAW 4
+#define NSEC_PER_SEC 1000000000LL
+#define MILLION 1000000
+
+long long llabs(long long val)
+{
+ if (val < 0)
+ val = -val;
+ return val;
+}
+
+unsigned long long ts_to_nsec(struct timespec ts)
+{
+ return ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec;
+}
+
+struct timespec nsec_to_ts(long long ns)
+{
+ struct timespec ts;
+
+ ts.tv_sec = ns/NSEC_PER_SEC;
+ ts.tv_nsec = ns%NSEC_PER_SEC;
+ return ts;
+}
+
+long long diff_timespec(struct timespec start, struct timespec end)
+{
+ long long start_ns, end_ns;
+
+ start_ns = ts_to_nsec(start);
+ end_ns = ts_to_nsec(end);
+ return end_ns - start_ns;
+}
+
+void get_monotonic_and_raw(struct timespec *mon, struct timespec *raw)
+{
+ struct timespec start, mid, end;
+ long long diff = 0, tmp;
+ int i;
+
+ clock_gettime(CLOCK_MONOTONIC, mon);
+ clock_gettime(CLOCK_MONOTONIC_RAW, raw);
+
+ /* Try to get a more tightly bound pairing */
+ for (i = 0; i < 3; i++) {
+ long long newdiff;
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ clock_gettime(CLOCK_MONOTONIC_RAW, &mid);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+
+ newdiff = diff_timespec(start, end);
+ if (diff == 0 || newdiff < diff) {
+ diff = newdiff;
+ *raw = mid;
+ tmp = (ts_to_nsec(start) + ts_to_nsec(end))/2;
+ *mon = nsec_to_ts(tmp);
+ }
+ }
+}
+
+long long get_ppm_drift(void)
+{
+ struct timespec mon_start, raw_start, mon_end, raw_end;
+ long long delta1, delta2, eppm;
+
+ get_monotonic_and_raw(&mon_start, &raw_start);
+
+ sleep(10);
+
+ get_monotonic_and_raw(&mon_end, &raw_end);
+
+ delta1 = diff_timespec(mon_start, mon_end);
+ delta2 = diff_timespec(raw_start, raw_end);
+
+ eppm = (delta1*MILLION)/delta2 - MILLION;
+ return eppm;
+}
+
+int check_tick_adj(long tickval)
+{
+ long long eppm, ppm;
+ struct timex tx1;
+
+ tx1.modes = ADJ_TICK;
+ tx1.modes |= ADJ_OFFSET;
+ tx1.modes |= ADJ_FREQUENCY;
+ tx1.offset = 0;
+ tx1.freq = 0;
+ tx1.tick = tickval;
+ adjtimex(&tx1);
+ sleep(1);
+
+ ppm = ((long long)tickval * MILLION)/10000 - MILLION;
+ printf("Estimating tick (act: %ld usec, %lld ppm): ", tickval, ppm);
+
+ eppm = get_ppm_drift();
+ printf("%lld usec, %lld ppm", 10000 + (10000 * eppm / MILLION), eppm);
+
+ tx1.modes = 0;
+ adjtimex(&tx1);
+ if (tx1.offset || tx1.freq || tx1.tick != tickval) {
+ printf("WARNING: Unexpected adjtimex return values, make sure
ntpd is not running. ");
+ return -1;
+ }
+
+ if (llabs(eppm - ppm) > 10) {
+ printf(" [FAILED]\n");
+ return -1;
+ }
+ printf(" [OK]\n");
+ return 0;
+}
+
+int main(int argv, char **argc)
+{
+ struct timespec raw;
+ long tick, err;
+ struct timex tx1;
+
+ err = 0;
+ setbuf(stdout, NULL);
+
+ if (clock_gettime(CLOCK_MONOTONIC_RAW, &raw)) {
+ printf("ERR: NO CLOCK_MONOTONIC_RAW\n");
+ return -1;
+ }
+
+ for (tick = 9000; tick < 11000; tick += 250)
+ if (check_tick_adj(tick)) {
+ err = 1;
+ break;
+ }
+
+ /* Reset things to zero */
+ tx1.modes = ADJ_TICK;
+ tx1.modes |= ADJ_OFFSET;
+ tx1.modes |= ADJ_FREQUENCY;
+ tx1.offset = 0;
+ tx1.freq = 0;
+ tx1.tick = 10000;
+ adjtimex(&tx1);
+
+ if (err)
+ return ksft_exit_fail();
+ return ksft_exit_pass();
+}
--
1.9.1
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