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[GIT PULL][PATCH 0/4] Timekeeping items for 4.13

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  [GIT PULL][PATCH 0/4] Timekeeping items for 4.13 John Stultz <john.stultz@linaro.org> - 2017-06-21 07:30 +0200
    [PATCH 4/4] kselftests: timers: Add test for frequency step John Stultz <john.stultz@linaro.org> - 2017-06-21 07:30 +0200
    [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD John Stultz <john.stultz@linaro.org> - 2017-06-21 07:30 +0200
      Re: [PATCH 2/4] time: Add warning about imminent deprecation of  CONFIG_GENERIC_TIME_VSYSCALL_OLD Paul Mackerras <paulus@ozlabs.org> - 2017-06-21 08:20 +0200
        Re: [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD John Stultz <john.stultz@linaro.org> - 2017-06-21 08:30 +0200
      Re: [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD Michael Ellerman <mpe@ellerman.id.au> - 2017-06-21 08:20 +0200

#1671359 — [GIT PULL][PATCH 0/4] Timekeeping items for 4.13

Just a small set of changes, the biggest changes being the
MONOTONIC_RAW handling cleanup, and a new kselftest from
Miroslav. Also a a clear warning deprecating
CONFIG_GENERIC_TIME_VSYSCALL_OLD, which affects ppc and ia64.

Let me know if you have any thoughts or objections!

thanks
-john

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>

The following changes since commit 8e6cec1c7c5afa489687c90be15d6ed82c742975:

  Merge branch 'clockevents/4.12-fixes' of https://git.linaro.org/people/daniel.lezcano/linux into timers/urgent (2017-06-20 12:50:32 +0200)

are available in the git repository at:

  https://git.linaro.org/people/john.stultz/linux.git fortglx/4.13/time

for you to fetch changes up to 767392565a3e618950fe1a5ff1ba11295f6332f4:

  kselftests: timers: Add test for frequency step (2017-06-20 22:14:45 -0700)

----------------------------------------------------------------
John Stultz (2):
  time: Clean up CLOCK_MONOTONIC_RAW time handling
  time: Add warning about imminent deprecation of
    CONFIG_GENERIC_TIME_VSYSCALL_OLD

Miroslav Lichvar (2):
  kselftests: timers: Fix inconsistency-check to not ignore first
    timestamp
  kselftests: timers: Add test for frequency step

 arch/arm64/kernel/vdso.c                           |   6 +-
 include/linux/timekeeper_internal.h                |   4 +-
 kernel/time/timekeeping.c                          |  46 ++--
 tools/testing/selftests/timers/Makefile            |   5 +-
 tools/testing/selftests/timers/freq-step.c         | 268 +++++++++++++++++++++
 .../testing/selftests/timers/inconsistency-check.c |   4 +-
 6 files changed, 303 insertions(+), 30 deletions(-)
 create mode 100644 tools/testing/selftests/timers/freq-step.c

-- 
2.7.4

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#1671361 — [PATCH 4/4] kselftests: timers: Add test for frequency step

From: Miroslav Lichvar <mlichvar@redhat.com>

This test checks the response of the system clock to frequency
steps made with adjtimex(). The frequency error and stability of
the CLOCK_MONOTONIC clock relative to the CLOCK_MONOTONIC_RAW clock
is measured in two intervals following the step. The test fails if
values from the second interval exceed specified limits.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 tools/testing/selftests/timers/Makefile    |   5 +-
 tools/testing/selftests/timers/freq-step.c | 268 +++++++++++++++++++++++++++++
 2 files changed, 271 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/timers/freq-step.c

diff --git a/tools/testing/selftests/timers/Makefile b/tools/testing/selftests/timers/Makefile
index 5fa1d7e9..5801bbe 100644
--- a/tools/testing/selftests/timers/Makefile
+++ b/tools/testing/selftests/timers/Makefile
@@ -1,6 +1,6 @@
 BUILD_FLAGS = -DKTEST
 CFLAGS += -O3 -Wl,-no-as-needed -Wall $(BUILD_FLAGS)
-LDFLAGS += -lrt -lpthread
+LDFLAGS += -lrt -lpthread -lm
 
 # these are all "safe" tests that don't modify
 # system time or require escalated privileges
@@ -8,7 +8,7 @@ TEST_GEN_PROGS = posix_timers nanosleep nsleep-lat set-timer-lat mqueue-lat \
 	     inconsistency-check raw_skew threadtest rtctest
 
 TEST_GEN_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex adjtick change_skew \
-		      skew_consistency clocksource-switch leap-a-day \
+		      skew_consistency clocksource-switch freq-step leap-a-day \
 		      leapcrash set-tai set-2038 set-tz
 
 
@@ -24,6 +24,7 @@ run_destructive_tests: run_tests
 	./change_skew
 	./skew_consistency
 	./clocksource-switch
+	./freq-step
 	./leap-a-day -s -i 10
 	./leapcrash
 	./set-tz
diff --git a/tools/testing/selftests/timers/freq-step.c b/tools/testing/selftests/timers/freq-step.c
new file mode 100644
index 0000000..e8c6183
--- /dev/null
+++ b/tools/testing/selftests/timers/freq-step.c
@@ -0,0 +1,268 @@
+/*
+ * This test checks the response of the system clock to frequency
+ * steps made with adjtimex(). The frequency error and stability of
+ * the CLOCK_MONOTONIC clock relative to the CLOCK_MONOTONIC_RAW clock
+ * is measured in two intervals following the step. The test fails if
+ * values from the second interval exceed specified limits.
+ *
+ * Copyright (C) Miroslav Lichvar <mlichvar@redhat.com>  2017
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * 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 <math.h>
+#include <stdio.h>
+#include <sys/timex.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+
+#define SAMPLES 100
+#define SAMPLE_READINGS 10
+#define MEAN_SAMPLE_INTERVAL 0.1
+#define STEP_INTERVAL 1.0
+#define MAX_PRECISION 100e-9
+#define MAX_FREQ_ERROR 10e-6
+#define MAX_STDDEV 1000e-9
+
+struct sample {
+	double offset;
+	double time;
+};
+
+static time_t mono_raw_base;
+static time_t mono_base;
+static long user_hz;
+static double precision;
+static double mono_freq_offset;
+
+static double diff_timespec(struct timespec *ts1, struct timespec *ts2)
+{
+	return ts1->tv_sec - ts2->tv_sec + (ts1->tv_nsec - ts2->tv_nsec) / 1e9;
+}
+
+static double get_sample(struct sample *sample)
+{
+	double delay, mindelay = 0.0;
+	struct timespec ts1, ts2, ts3;
+	int i;
+
+	for (i = 0; i < SAMPLE_READINGS; i++) {
+		clock_gettime(CLOCK_MONOTONIC_RAW, &ts1);
+		clock_gettime(CLOCK_MONOTONIC, &ts2);
+		clock_gettime(CLOCK_MONOTONIC_RAW, &ts3);
+
+		ts1.tv_sec -= mono_raw_base;
+		ts2.tv_sec -= mono_base;
+		ts3.tv_sec -= mono_raw_base;
+
+		delay = diff_timespec(&ts3, &ts1);
+		if (delay <= 1e-9) {
+			i--;
+			continue;
+		}
+
+		if (!i || delay < mindelay) {
+			sample->offset = diff_timespec(&ts2, &ts1);
+			sample->offset -= delay / 2.0;
+			sample->time = ts1.tv_sec + ts1.tv_nsec / 1e9;
+			mindelay = delay;
+		}
+	}
+
+	return mindelay;
+}
+
+static void reset_ntp_error(void)
+{
+	struct timex txc;
+
+	txc.modes = ADJ_SETOFFSET;
+	txc.time.tv_sec = 0;
+	txc.time.tv_usec = 0;
+
+	if (adjtimex(&txc) < 0) {
+		perror("[FAIL] adjtimex");
+		ksft_exit_fail();
+	}
+}
+
+static void set_frequency(double freq)
+{
+	struct timex txc;
+	int tick_offset;
+
+	tick_offset = 1e6 * freq / user_hz;
+
+	txc.modes = ADJ_TICK | ADJ_FREQUENCY;
+	txc.tick = 1000000 / user_hz + tick_offset;
+	txc.freq = (1e6 * freq - user_hz * tick_offset) * (1 << 16);
+
+	if (adjtimex(&txc) < 0) {
+		perror("[FAIL] adjtimex");
+		ksft_exit_fail();
+	}
+}
+
+static void regress(struct sample *samples, int n, double *intercept,
+		    double *slope, double *r_stddev, double *r_max)
+{
+	double x, y, r, x_sum, y_sum, xy_sum, x2_sum, r2_sum;
+	int i;
+
+	x_sum = 0.0, y_sum = 0.0, xy_sum = 0.0, x2_sum = 0.0;
+
+	for (i = 0; i < n; i++) {
+		x = samples[i].time;
+		y = samples[i].offset;
+
+		x_sum += x;
+		y_sum += y;
+		xy_sum += x * y;
+		x2_sum += x * x;
+	}
+
+	*slope = (xy_sum - x_sum * y_sum / n) / (x2_sum - x_sum * x_sum / n);
+	*intercept = (y_sum - *slope * x_sum) / n;
+
+	*r_max = 0.0, r2_sum = 0.0;
+
+	for (i = 0; i < n; i++) {
+		x = samples[i].time;
+		y = samples[i].offset;
+		r = fabs(x * *slope + *intercept - y);
+		if (*r_max < r)
+			*r_max = r;
+		r2_sum += r * r;
+	}
+
+	*r_stddev = sqrt(r2_sum / n);
+}
+
+static int run_test(int calibration, double freq_base, double freq_step)
+{
+	struct sample samples[SAMPLES];
+	double intercept, slope, stddev1, max1, stddev2, max2;
+	double freq_error1, freq_error2;
+	int i;
+
+	set_frequency(freq_base);
+
+	for (i = 0; i < 10; i++)
+		usleep(1e6 * MEAN_SAMPLE_INTERVAL / 10);
+
+	reset_ntp_error();
+
+	set_frequency(freq_base + freq_step);
+
+	for (i = 0; i < 10; i++)
+		usleep(rand() % 2000000 * STEP_INTERVAL / 10);
+
+	set_frequency(freq_base);
+
+	for (i = 0; i < SAMPLES; i++) {
+		usleep(rand() % 2000000 * MEAN_SAMPLE_INTERVAL);
+		get_sample(&samples[i]);
+	}
+
+	if (calibration) {
+		regress(samples, SAMPLES, &intercept, &slope, &stddev1, &max1);
+		mono_freq_offset = slope;
+		printf("CLOCK_MONOTONIC_RAW frequency offset: %11.3f ppm\n",
+		       1e6 * mono_freq_offset);
+		return 0;
+	}
+
+	regress(samples, SAMPLES / 2, &intercept, &slope, &stddev1, &max1);
+	freq_error1 = slope * (1.0 - mono_freq_offset) - mono_freq_offset -
+			freq_base;
+
+	regress(samples + SAMPLES / 2, SAMPLES / 2, &intercept, &slope,
+		&stddev2, &max2);
+	freq_error2 = slope * (1.0 - mono_freq_offset) - mono_freq_offset -
+			freq_base;
+
+	printf("%6.0f %+10.3f %6.0f %7.0f %+10.3f %6.0f %7.0f\t",
+	       1e6 * freq_step,
+	       1e6 * freq_error1, 1e9 * stddev1, 1e9 * max1,
+	       1e6 * freq_error2, 1e9 * stddev2, 1e9 * max2);
+
+	if (fabs(freq_error2) > MAX_FREQ_ERROR || stddev2 > MAX_STDDEV) {
+		printf("[FAIL]\n");
+		return 1;
+	}
+
+	printf("[OK]\n");
+	return 0;
+}
+
+static void init_test(void)
+{
+	struct timespec ts;
+	struct sample sample;
+
+	if (clock_gettime(CLOCK_MONOTONIC_RAW, &ts)) {
+		perror("[FAIL] clock_gettime(CLOCK_MONOTONIC_RAW)");
+		ksft_exit_fail();
+	}
+
+	mono_raw_base = ts.tv_sec;
+
+	if (clock_gettime(CLOCK_MONOTONIC, &ts)) {
+		perror("[FAIL] clock_gettime(CLOCK_MONOTONIC)");
+		ksft_exit_fail();
+	}
+
+	mono_base = ts.tv_sec;
+
+	user_hz = sysconf(_SC_CLK_TCK);
+
+	precision = get_sample(&sample) / 2.0;
+	printf("CLOCK_MONOTONIC_RAW+CLOCK_MONOTONIC precision: %.0f ns\t\t",
+	       1e9 * precision);
+
+	if (precision > MAX_PRECISION) {
+		printf("[SKIP]\n");
+		ksft_exit_skip();
+	}
+
+	printf("[OK]\n");
+	srand(ts.tv_sec ^ ts.tv_nsec);
+
+	run_test(1, 0.0, 0.0);
+}
+
+int main(int argc, char **argv)
+{
+	double freq_base, freq_step;
+	int i, j, fails = 0;
+
+	init_test();
+
+	printf("Checking response to frequency step:\n");
+	printf("  Step           1st interval              2nd interval\n");
+	printf("             Freq    Dev     Max       Freq    Dev     Max\n");
+
+	for (i = 2; i >= 0; i--) {
+		for (j = 0; j < 5; j++) {
+			freq_base = (rand() % (1 << 24) - (1 << 23)) / 65536e6;
+			freq_step = 10e-6 * (1 << (6 * i));
+			fails += run_test(0, freq_base, freq_step);
+		}
+	}
+
+	set_frequency(0.0);
+
+	if (fails)
+		ksft_exit_fail();
+
+	ksft_exit_pass();
+}
-- 
2.7.4

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#1671362 — [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD

CONFIG_GENERIC_TIME_VSYSCALL_OLD was introduced five years ago
to allow a transition from the old vsyscall implementations to
the new method (which simplified internal accounting and made
timekeeping more precise).

However, PPC and IA64 have yet to make the transition, despite
in some cases me sending test patches to try to help it along.

http://patches.linaro.org/patch/30501/
http://patches.linaro.org/patch/35412/

If its helpful, my last pass at the patches can be found here:
https://git.linaro.org/people/john.stultz/linux.git dev/oldvsyscall-cleanup

So I think its time to set a deadline and make it clear this
is going away. So this patch adds warnings about this
functionality being dropped. Likely to be in v4.15.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/timekeeping.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 0454bfa..cedafa0 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -516,6 +516,7 @@ static void halt_fast_timekeeper(struct timekeeper *tk)
 }
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
+#warning Please contact your maintainers, as GENERIC_TIME_VSYSCALL_OLD compatibity will disappear soon.
 
 static inline void update_vsyscall(struct timekeeper *tk)
 {
-- 
2.7.4

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#1671381 — Re: [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD

On Tue, Jun 20, 2017 at 10:21:31PM -0700, John Stultz wrote:
> CONFIG_GENERIC_TIME_VSYSCALL_OLD was introduced five years ago
> to allow a transition from the old vsyscall implementations to
> the new method (which simplified internal accounting and made
> timekeeping more precise).
> 
> However, PPC and IA64 have yet to make the transition, despite
> in some cases me sending test patches to try to help it along.

Did you see my patch converting PPC to the new method?  Did you have
any comments on it?

Regards,
Paul.

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#1671389 — Re: [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD

On Tue, Jun 20, 2017 at 11:11 PM, Paul Mackerras <paulus@ozlabs.org> wrote:
> On Tue, Jun 20, 2017 at 10:21:31PM -0700, John Stultz wrote:
>> CONFIG_GENERIC_TIME_VSYSCALL_OLD was introduced five years ago
>> to allow a transition from the old vsyscall implementations to
>> the new method (which simplified internal accounting and made
>> timekeeping more precise).
>>
>> However, PPC and IA64 have yet to make the transition, despite
>> in some cases me sending test patches to try to help it along.
>
> Did you see my patch converting PPC to the new method?  Did you have
> any comments on it?

Oh, somehow I missed it!  My apologies. That's great to see! It
roughly looks ok, but I'll need to look at it closer with fresh eyes
(and honestly, its complex enough I'm not sure I will be able to fully
mentally validate it :)

But I'll try to give it a look tomorrow.

thanks
-john

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#1671383 — Re: [PATCH 2/4] time: Add warning about imminent deprecation of CONFIG_GENERIC_TIME_VSYSCALL_OLD

John Stultz <john.stultz@linaro.org> writes:

> CONFIG_GENERIC_TIME_VSYSCALL_OLD was introduced five years ago
> to allow a transition from the old vsyscall implementations to
> the new method (which simplified internal accounting and made
> timekeeping more precise).
>
> However, PPC and IA64 have yet to make the transition, despite
> in some cases me sending test patches to try to help it along.

Any chance you can review/ack the patch from Paul to convert powerpc
to the new style? :D

cheers

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