Fix time/tst-cpuclock1 intermitent failures

This test fails intermittently in systems with heavy load as
CLOCK_PROCESS_CPUTIME_ID is subject to scheduler pressure.  Thus the
test boundaries were relaxed to keep it from failing on such systems.

A refactor of the spent time checking was made with some support
functions.  With the advantage to representing time jitter in percent
of the target.

The values used by the test boundaries are all empirical.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Lucas A. M. Magalhaes 2020-07-10 19:41:06 -03:00 committed by Tulio Magno Quites Machado Filho
parent 7c7bcf3634
commit 04deeaa9ea
5 changed files with 415 additions and 30 deletions

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@ -238,6 +238,7 @@ tests = \
tst-test_compare \
tst-test_compare_blob \
tst-test_compare_string \
tst-timespec \
tst-xreadlink \
tst-xsigstack \

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@ -19,6 +19,8 @@
#include <support/timespec.h>
#include <stdio.h>
#include <stdint.h>
#include <assert.h>
#include <intprops.h>
void
test_timespec_before_impl (const char *file, int line,
@ -57,3 +59,65 @@ test_timespec_equal_or_after_impl (const char *file, int line,
(intmax_t) diff.tv_sec, (intmax_t) diff.tv_nsec);
}
}
/* Convert TIME to nanoseconds stored in a long.
Returns long maximum or minimum if the conversion overflows
or underflows, respectively. */
long
support_timespec_ns (struct timespec time)
{
long time_ns;
if (INT_MULTIPLY_WRAPV(time.tv_sec, TIMESPEC_HZ, &time_ns))
{
return (time.tv_sec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
}
if (INT_ADD_WRAPV(time_ns, time.tv_nsec, &time_ns))
{
return (time.tv_nsec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
}
return time_ns;
}
/* Returns time normalized timespec with .tv_nsec < TIMESPEC_HZ
and the whole seconds added to .tv_sec. If an overflow or
underflow occurs the values are clamped to its maximum or
minimum respectively. */
struct timespec
support_timespec_normalize (struct timespec time)
{
struct timespec norm;
if (INT_ADD_WRAPV (time.tv_sec, (time.tv_nsec / TIMESPEC_HZ), &norm.tv_sec))
{
norm.tv_sec = (time.tv_nsec < 0) ? TYPE_MINIMUM (time_t): TYPE_MAXIMUM (time_t);
norm.tv_nsec = (time.tv_nsec < 0) ? -1 * (TIMESPEC_HZ - 1) : TIMESPEC_HZ - 1;
return norm;
}
norm.tv_nsec = time.tv_nsec % TIMESPEC_HZ;
return norm;
}
/* Returns TRUE if the observed time is within the given percentage
bounds of the expected time, and FALSE otherwise.
For example the call
support_timespec_check_in_range(expected, observed, 0.5, 1.2);
will check if
0.5 of expected <= observed <= 1.2 of expected
In other words it will check if observed time is within 50% to
120% of the expected time. */
int
support_timespec_check_in_range (struct timespec expected, struct timespec observed,
double lower_bound, double upper_bound)
{
assert (upper_bound >= lower_bound);
long expected_norm, observed_norm;
expected_norm = support_timespec_ns (expected);
/* Don't divide by zero */
assert(expected_norm != 0);
observed_norm = support_timespec_ns (observed);
double ratio = (double)observed_norm / expected_norm;
return (lower_bound <= ratio && ratio <= upper_bound);
}

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@ -48,6 +48,14 @@ void test_timespec_equal_or_after_impl (const char *file, int line,
const struct timespec left,
const struct timespec right);
long support_timespec_ns (struct timespec time);
struct timespec support_timespec_normalize (struct timespec time);
int support_timespec_check_in_range (struct timespec expected, struct timespec observed,
double lower_bound, double upper_bound);
/* Check that the timespec on the left represents a time before the
time on the right. */
#define TEST_TIMESPEC_BEFORE(left, right) \

320
support/tst-timespec.c Normal file
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@ -0,0 +1,320 @@
/* Test for support_timespec_check_in_range function.
Copyright (C) 2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <support/timespec.h>
#include <support/check.h>
#include <limits.h>
#define TIMESPEC_HZ 1000000000
struct timespec_ns_test_case
{
struct timespec time;
long time_ns;
};
struct timespec_norm_test_case
{
struct timespec time;
struct timespec norm;
};
struct timespec_test_case
{
struct timespec expected;
struct timespec observed;
double upper_bound;
double lower_bound;
int result;
};
/* Test cases for timespec_ns */
struct timespec_ns_test_case ns_cases[] = {
{.time = {.tv_sec = 0, .tv_nsec = 0},
.time_ns = 0,
},
{.time = {.tv_sec = 0, .tv_nsec = 1},
.time_ns = 1,
},
{.time = {.tv_sec = 1, .tv_nsec = 0},
.time_ns = TIMESPEC_HZ,
},
{.time = {.tv_sec = 1, .tv_nsec = 1},
.time_ns = TIMESPEC_HZ + 1,
},
{.time = {.tv_sec = 0, .tv_nsec = -1},
.time_ns = -1,
},
{.time = {.tv_sec = -1, .tv_nsec = 0},
.time_ns = -TIMESPEC_HZ,
},
{.time = {.tv_sec = -1, .tv_nsec = -1},
.time_ns = -TIMESPEC_HZ - 1,
},
{.time = {.tv_sec = 1, .tv_nsec = -1},
.time_ns = TIMESPEC_HZ - 1,
},
{.time = {.tv_sec = -1, .tv_nsec = 1},
.time_ns = -TIMESPEC_HZ + 1,
},
/* Overflow bondary by 2 */
{.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ - 1},
.time_ns = LONG_MAX - 1,
},
/* Overflow bondary */
{.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ},
.time_ns = LONG_MAX,
},
/* Underflow bondary by 1 */
{.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ + 1},
.time_ns = LONG_MIN + 1,
},
/* Underflow bondary */
{.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ},
.time_ns = LONG_MIN,
},
/* Multiplication overflow */
{.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ + 1, .tv_nsec = 1},
.time_ns = LONG_MAX,
},
/* Multiplication underflow */
{.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ - 1, .tv_nsec = -1},
.time_ns = LONG_MIN,
},
/* Sum overflows */
{.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ + 1},
.time_ns = LONG_MAX,
},
/* Sum underflow */
{.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ - 1},
.time_ns = LONG_MIN,
}
};
/* Test cases for timespec_norm */
struct timespec_norm_test_case norm_cases[] = {
/* Positive cases */
{.time = {.tv_sec = 0, .tv_nsec = 0},
.norm = {.tv_sec = 0, .tv_nsec = 0}
},
{.time = {.tv_sec = 1, .tv_nsec = 0},
.norm = {.tv_sec = 1, .tv_nsec = 0}
},
{.time = {.tv_sec = 0, .tv_nsec = 1},
.norm = {.tv_sec = 0, .tv_nsec = 1}
},
{.time = {.tv_sec = 0, .tv_nsec = TIMESPEC_HZ},
.norm = {.tv_sec = 1, .tv_nsec = 0}
},
{.time = {.tv_sec = 0, .tv_nsec = TIMESPEC_HZ + 1},
.norm = {.tv_sec = 1, .tv_nsec = 1}
},
{.time = {.tv_sec = 1, .tv_nsec = TIMESPEC_HZ},
.norm = {.tv_sec = 2, .tv_nsec = 0}
},
{.time = {.tv_sec = 1, .tv_nsec = TIMESPEC_HZ + 1},
.norm = {.tv_sec = 2, .tv_nsec = 1}
},
/* Negative cases */
{.time = {.tv_sec = 0, .tv_nsec = -TIMESPEC_HZ},
.norm = {.tv_sec = -1, .tv_nsec = 0}
},
{.time = {.tv_sec = 0, .tv_nsec = -TIMESPEC_HZ - 1},
.norm = {.tv_sec = -1, .tv_nsec = -1}
},
{.time = {.tv_sec = -1, .tv_nsec = -TIMESPEC_HZ},
.norm = {.tv_sec = -2, .tv_nsec = 0}
},
{.time = {.tv_sec = -1, .tv_nsec = -TIMESPEC_HZ - 1},
.norm = {.tv_sec = -2, .tv_nsec = -1}
},
/* Overflow bondary by 2 */
{.time = {.tv_sec = LONG_MAX - 2, .tv_nsec = TIMESPEC_HZ + 1},
.norm = {.tv_sec = LONG_MAX - 1, 1},
},
/* Overflow bondary by 1 */
{.time = {.tv_sec = LONG_MAX - 1, .tv_nsec = TIMESPEC_HZ + 1},
.norm = {.tv_sec = LONG_MAX, .tv_nsec = 1},
},
/* Underflow bondary by 2 */
{.time = {.tv_sec = LONG_MIN + 2, .tv_nsec = -TIMESPEC_HZ - 1},
.norm = {.tv_sec = LONG_MIN + 1, -1},
},
/* Underflow bondary by 1 */
{.time = {.tv_sec = LONG_MIN + 1, .tv_nsec = -TIMESPEC_HZ - 1},
.norm = {.tv_sec = LONG_MIN, .tv_nsec = -1},
},
/* SUM overflow */
{.time = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
.norm = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 1},
},
/* SUM underflow */
{.time = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
.norm = {.tv_sec = LONG_MIN, .tv_nsec = -1 * (TIMESPEC_HZ - 1)},
}
};
/* Test cases for timespec_check_in_range */
struct timespec_test_case check_cases[] = {
/* 0 - In range */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 1, .tv_nsec = 0},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 1 - Out of range */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 2, .tv_nsec = 0},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 2 - Upper Bound */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 2, .tv_nsec = 0},
.upper_bound = 2, .lower_bound = 1, .result = 1,
},
/* 3 - Lower Bound */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 0, .tv_nsec = 0},
.upper_bound = 1, .lower_bound = 0, .result = 1,
},
/* 4 - Out of range by nanosecs */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 1, .tv_nsec = 500},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 5 - In range by nanosecs */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 1, .tv_nsec = 50000},
.upper_bound = 1.3, .lower_bound = 1, .result = 1,
},
/* 6 - Big nanosecs */
{.expected = {.tv_sec = 1, .tv_nsec = 0},
.observed = {.tv_sec = 0, .tv_nsec = 4000000},
.upper_bound = 1, .lower_bound = .001, .result = 1,
},
/* 7 - In range Negative values */
{.expected = {.tv_sec = -1, .tv_nsec = 0},
.observed = {.tv_sec = -1, .tv_nsec = 0},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 8 - Out of range Negative values */
{.expected = {.tv_sec = -1, .tv_nsec = 0},
.observed = {.tv_sec = -1, .tv_nsec = 0},
.upper_bound = -1, .lower_bound = -1, .result = 0,
},
/* 9 - Negative values with negative nanosecs */
{.expected = {.tv_sec = -1, .tv_nsec = 0},
.observed = {.tv_sec = -1, .tv_nsec = -2000},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 10 - Strict bounds */
{.expected = {.tv_sec = -1, .tv_nsec = 0},
.observed = {.tv_sec = -1, .tv_nsec = -20000},
.upper_bound = 1.00002, .lower_bound = 1.0000191, .result = 1,
},
/* 11 - Strict bounds with loose upper bound */
{.expected = {.tv_sec = 1, .tv_nsec = 20000},
.observed = {.tv_sec = 1, .tv_nsec = 30000},
.upper_bound = 1.0000100000, .lower_bound = 1.0000099998, .result = 1,
},
/* 12 - Strict bounds with loose lower bound */
{.expected = {.tv_sec = 1, .tv_nsec = 20000},
.observed = {.tv_sec = 1, .tv_nsec = 30000},
.upper_bound = 1.0000099999, .lower_bound = 1.00000999979, .result = 1,
},
/* 13 - Strict bounds highest precision */
{.expected = {.tv_sec = 1, .tv_nsec = 20000},
.observed = {.tv_sec = 1, .tv_nsec = 30000},
.upper_bound = 1.00000999980001, .lower_bound = 1.00000999979999, .result = 1,
},
/* Maximum/Minimum long values */
/* 14 */
{.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 1},
.observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 2},
.upper_bound = 1, .lower_bound = .9, .result = 1,
},
/* 15 - support_timespec_ns overflow */
{.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
.observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 16 - support_timespec_ns overflow + underflow */
{.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
.observed = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 17 - support_timespec_ns underflow */
{.expected = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
.observed = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 18 - support_timespec_ns underflow + overflow */
{.expected = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
.observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 19 - Biggest division */
{.expected = {.tv_sec = LONG_MAX / TIMESPEC_HZ , .tv_nsec = TIMESPEC_HZ - 1},
.observed = {.tv_sec = 0, .tv_nsec = 1},
.upper_bound = 1, .lower_bound = 1.0842021724855044e-19, .result = 1,
},
/* 20 - Lowest division */
{.expected = {.tv_sec = 0, .tv_nsec = 1},
.observed = {.tv_sec = LONG_MAX / TIMESPEC_HZ , .tv_nsec = TIMESPEC_HZ - 1},
.upper_bound = LONG_MAX, .lower_bound = 1, .result = 1,
},
};
static int
do_test (void)
{
int i = 0;
int ntests = sizeof (ns_cases) / sizeof (ns_cases[0]);
printf("Testing support_timespec_ns\n");
for (i = 0; i < ntests; i++)
{
TEST_COMPARE (support_timespec_ns (ns_cases[i].time),
ns_cases[i].time_ns);
}
ntests = sizeof (norm_cases) / sizeof (norm_cases[0]);
struct timespec result;
printf("Testing support_timespec_normalize\n");
for (i = 0; i < ntests; i++)
{
result = support_timespec_normalize (norm_cases[i].time);
TEST_COMPARE (norm_cases[i].norm.tv_sec, result.tv_sec);
TEST_COMPARE (norm_cases[i].norm.tv_nsec, result.tv_nsec);
}
ntests = sizeof (check_cases) / sizeof (check_cases[0]);
printf("Testing support_timespec_check_in_range\n");
for (i = 0; i < ntests; i++)
{
/* Its hard to find which test failed with just the TEST_COMPARE report.
So here we print every running testcase as well. */
printf("Test case %d\n", i);
TEST_COMPARE (support_timespec_check_in_range
(check_cases[i].expected, check_cases[i].observed,
check_cases[i].lower_bound,
check_cases[i].upper_bound), check_cases[i].result);
}
return 0;
}
#include <support/test-driver.c>

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@ -26,6 +26,7 @@
#include <signal.h>
#include <stdint.h>
#include <sys/wait.h>
#include <support/timespec.h>
/* This function is intended to rack up both user and system time. */
static void
@ -155,16 +156,12 @@ do_test (void)
printf ("live PID %d after sleep => %ju.%.9ju\n",
child, (uintmax_t) after.tv_sec, (uintmax_t) after.tv_nsec);
struct timespec diff = { .tv_sec = after.tv_sec - before.tv_sec,
.tv_nsec = after.tv_nsec - before.tv_nsec };
if (diff.tv_nsec < 0)
{
--diff.tv_sec;
diff.tv_nsec += 1000000000;
}
if (diff.tv_sec != 0
|| diff.tv_nsec > 600000000
|| diff.tv_nsec < 100000000)
/* The bound values are empirically defined by testing this code over high cpu
usage and different nice values. Of all the values we keep the 90th
percentile of values and use those values for our testing allowed range. */
struct timespec diff = timespec_sub (support_timespec_normalize (after),
support_timespec_normalize (before));
if (!support_timespec_check_in_range (sleeptime, diff, .9, 1.1))
{
printf ("before - after %ju.%.9ju outside reasonable range\n",
(uintmax_t) diff.tv_sec, (uintmax_t) diff.tv_nsec);
@ -194,19 +191,16 @@ do_test (void)
}
else
{
struct timespec d = { .tv_sec = afterns.tv_sec - after.tv_sec,
.tv_nsec = afterns.tv_nsec - after.tv_nsec };
if (d.tv_nsec < 0)
{
--d.tv_sec;
d.tv_nsec += 1000000000;
}
if (d.tv_sec > 0
|| d.tv_nsec < sleeptime.tv_nsec
|| d.tv_nsec > sleeptime.tv_nsec * 2)
/* The bound values are empirically defined by testing this code over
high cpu usage and different nice values. Of all the values we keep
the 90th percentile of values and use those values for our testing
allowed range. */
diff = timespec_sub (support_timespec_normalize (afterns),
support_timespec_normalize (after));
if (!support_timespec_check_in_range (sleeptime, diff, .9, 1.2))
{
printf ("nanosleep time %ju.%.9ju outside reasonable range\n",
(uintmax_t) d.tv_sec, (uintmax_t) d.tv_nsec);
(uintmax_t) diff.tv_sec, (uintmax_t) diff.tv_nsec);
result = 1;
}
}
@ -240,15 +234,13 @@ do_test (void)
/* Should be close to 0.6. */
printf ("dead PID %d => %ju.%.9ju\n",
child, (uintmax_t) dead.tv_sec, (uintmax_t) dead.tv_nsec);
diff.tv_sec = dead.tv_sec - after.tv_sec;
diff.tv_nsec = dead.tv_nsec - after.tv_nsec;
if (diff.tv_nsec < 0)
{
--diff.tv_sec;
diff.tv_nsec += 1000000000;
}
if (diff.tv_sec != 0 || diff.tv_nsec > 200000000)
/* The bound values are empirically defined by testing this code over high cpu
usage and different nice values. Of all the values we keep the 90th
percentile of values and use those values for our testing allowed range. */
diff = timespec_sub (support_timespec_normalize (dead),
support_timespec_normalize (after));
sleeptime.tv_nsec = 100000000;
if (!support_timespec_check_in_range (sleeptime, diff, .9, 1.2))
{
printf ("dead - after %ju.%.9ju outside reasonable range\n",
(uintmax_t) diff.tv_sec, (uintmax_t) diff.tv_nsec);