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https://github.com/torvalds/linux
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4b4f0876ab
The only caller of this code (time_stats) always knows the weights and whether or not any information has been collected. Pass this information into the mean and variance code so that it doesn't have to store that information. This reduces the structure size from 24 to 16 bytes, which shrinks each time_stats counter to 192 bytes from 208. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
247 lines
8.3 KiB
C
247 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <kunit/test.h>
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#include "mean_and_variance.h"
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#define MAX_SQR (SQRT_U64_MAX*SQRT_U64_MAX)
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static void mean_and_variance_basic_test(struct kunit *test)
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{
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struct mean_and_variance s = {};
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mean_and_variance_update(&s, 2);
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mean_and_variance_update(&s, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_mean(s), 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_variance(s), 0);
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KUNIT_EXPECT_EQ(test, s.n, 2);
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mean_and_variance_update(&s, 4);
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mean_and_variance_update(&s, 4);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_mean(s), 3);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_variance(s), 1);
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KUNIT_EXPECT_EQ(test, s.n, 4);
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}
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/*
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* Test values computed using a spreadsheet from the psuedocode at the bottom:
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* https://fanf2.user.srcf.net/hermes/doc/antiforgery/stats.pdf
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*/
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static void mean_and_variance_weighted_test(struct kunit *test)
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{
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struct mean_and_variance_weighted s = { };
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mean_and_variance_weighted_update(&s, 10, false, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), 10);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 0);
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mean_and_variance_weighted_update(&s, 20, true, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), 12);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 18);
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mean_and_variance_weighted_update(&s, 30, true, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), 16);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 72);
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s = (struct mean_and_variance_weighted) { };
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mean_and_variance_weighted_update(&s, -10, false, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), -10);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 0);
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mean_and_variance_weighted_update(&s, -20, true, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), -12);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 18);
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mean_and_variance_weighted_update(&s, -30, true, 2);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 2), -16);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 2), 72);
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}
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static void mean_and_variance_weighted_advanced_test(struct kunit *test)
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{
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struct mean_and_variance_weighted s = { };
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bool initted = false;
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s64 i;
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for (i = 10; i <= 100; i += 10) {
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mean_and_variance_weighted_update(&s, i, initted, 8);
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initted = true;
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}
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 8), 11);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 8), 107);
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s = (struct mean_and_variance_weighted) { };
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initted = false;
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for (i = -10; i >= -100; i -= 10) {
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mean_and_variance_weighted_update(&s, i, initted, 8);
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initted = true;
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}
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(s, 8), -11);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_variance(s, 8), 107);
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}
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static void do_mean_and_variance_test(struct kunit *test,
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s64 initial_value,
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s64 initial_n,
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s64 n,
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unsigned weight,
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s64 *data,
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s64 *mean,
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s64 *stddev,
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s64 *weighted_mean,
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s64 *weighted_stddev)
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{
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struct mean_and_variance mv = {};
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struct mean_and_variance_weighted vw = { };
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for (unsigned i = 0; i < initial_n; i++) {
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mean_and_variance_update(&mv, initial_value);
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mean_and_variance_weighted_update(&vw, initial_value, false, weight);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_mean(mv), initial_value);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_stddev(mv), 0);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(vw, weight), initial_value);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_stddev(vw, weight),0);
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}
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for (unsigned i = 0; i < n; i++) {
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mean_and_variance_update(&mv, data[i]);
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mean_and_variance_weighted_update(&vw, data[i], true, weight);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_mean(mv), mean[i]);
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KUNIT_EXPECT_EQ(test, mean_and_variance_get_stddev(mv), stddev[i]);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_mean(vw, weight), weighted_mean[i]);
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KUNIT_EXPECT_EQ(test, mean_and_variance_weighted_get_stddev(vw, weight),weighted_stddev[i]);
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}
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KUNIT_EXPECT_EQ(test, mv.n, initial_n + n);
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}
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/* Test behaviour with a single outlier, then back to steady state: */
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static void mean_and_variance_test_1(struct kunit *test)
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{
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s64 d[] = { 100, 10, 10, 10, 10, 10, 10 };
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s64 mean[] = { 22, 21, 20, 19, 18, 17, 16 };
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s64 stddev[] = { 32, 29, 28, 27, 26, 25, 24 };
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s64 weighted_mean[] = { 32, 27, 22, 19, 17, 15, 14 };
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s64 weighted_stddev[] = { 38, 35, 31, 27, 24, 21, 18 };
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do_mean_and_variance_test(test, 10, 6, ARRAY_SIZE(d), 2,
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d, mean, stddev, weighted_mean, weighted_stddev);
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}
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static void mean_and_variance_test_2(struct kunit *test)
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{
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s64 d[] = { 100, 10, 10, 10, 10, 10, 10 };
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s64 mean[] = { 10, 10, 10, 10, 10, 10, 10 };
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s64 stddev[] = { 9, 9, 9, 9, 9, 9, 9 };
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s64 weighted_mean[] = { 32, 27, 22, 19, 17, 15, 14 };
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s64 weighted_stddev[] = { 38, 35, 31, 27, 24, 21, 18 };
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do_mean_and_variance_test(test, 10, 6, ARRAY_SIZE(d), 2,
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d, mean, stddev, weighted_mean, weighted_stddev);
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}
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/* Test behaviour where we switch from one steady state to another: */
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static void mean_and_variance_test_3(struct kunit *test)
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{
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s64 d[] = { 100, 100, 100, 100, 100 };
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s64 mean[] = { 22, 32, 40, 46, 50 };
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s64 stddev[] = { 32, 39, 42, 44, 45 };
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s64 weighted_mean[] = { 32, 49, 61, 71, 78 };
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s64 weighted_stddev[] = { 38, 44, 44, 41, 38 };
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do_mean_and_variance_test(test, 10, 6, ARRAY_SIZE(d), 2,
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d, mean, stddev, weighted_mean, weighted_stddev);
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}
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static void mean_and_variance_test_4(struct kunit *test)
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{
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s64 d[] = { 100, 100, 100, 100, 100 };
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s64 mean[] = { 10, 11, 12, 13, 14 };
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s64 stddev[] = { 9, 13, 15, 17, 19 };
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s64 weighted_mean[] = { 32, 49, 61, 71, 78 };
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s64 weighted_stddev[] = { 38, 44, 44, 41, 38 };
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do_mean_and_variance_test(test, 10, 6, ARRAY_SIZE(d), 2,
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d, mean, stddev, weighted_mean, weighted_stddev);
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}
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static void mean_and_variance_fast_divpow2(struct kunit *test)
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{
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s64 i;
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u8 d;
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for (i = 0; i < 100; i++) {
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d = 0;
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KUNIT_EXPECT_EQ(test, fast_divpow2(i, d), div_u64(i, 1LLU << d));
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KUNIT_EXPECT_EQ(test, abs(fast_divpow2(-i, d)), div_u64(i, 1LLU << d));
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for (d = 1; d < 32; d++) {
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KUNIT_EXPECT_EQ_MSG(test, abs(fast_divpow2(i, d)),
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div_u64(i, 1 << d), "%lld %u", i, d);
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KUNIT_EXPECT_EQ_MSG(test, abs(fast_divpow2(-i, d)),
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div_u64(i, 1 << d), "%lld %u", -i, d);
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}
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}
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}
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static void mean_and_variance_u128_basic_test(struct kunit *test)
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{
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u128_u a = u64s_to_u128(0, U64_MAX);
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u128_u a1 = u64s_to_u128(0, 1);
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u128_u b = u64s_to_u128(1, 0);
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u128_u c = u64s_to_u128(0, 1LLU << 63);
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u128_u c2 = u64s_to_u128(U64_MAX, U64_MAX);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_add(a, a1)), 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_add(a, a1)), 0);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_add(a1, a)), 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_add(a1, a)), 0);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_sub(b, a1)), U64_MAX);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_sub(b, a1)), 0);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_shl(c, 1)), 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_shl(c, 1)), 0);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_square(U64_MAX)), U64_MAX - 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_square(U64_MAX)), 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_div(b, 2)), 1LLU << 63);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_div(c2, 2)), U64_MAX >> 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_div(c2, 2)), U64_MAX);
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KUNIT_EXPECT_EQ(test, u128_hi(u128_div(u128_shl(u64_to_u128(U64_MAX), 32), 2)), U32_MAX >> 1);
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KUNIT_EXPECT_EQ(test, u128_lo(u128_div(u128_shl(u64_to_u128(U64_MAX), 32), 2)), U64_MAX << 31);
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}
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static struct kunit_case mean_and_variance_test_cases[] = {
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KUNIT_CASE(mean_and_variance_fast_divpow2),
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KUNIT_CASE(mean_and_variance_u128_basic_test),
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KUNIT_CASE(mean_and_variance_basic_test),
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KUNIT_CASE(mean_and_variance_weighted_test),
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KUNIT_CASE(mean_and_variance_weighted_advanced_test),
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KUNIT_CASE(mean_and_variance_test_1),
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KUNIT_CASE(mean_and_variance_test_2),
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KUNIT_CASE(mean_and_variance_test_3),
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KUNIT_CASE(mean_and_variance_test_4),
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{}
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};
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static struct kunit_suite mean_and_variance_test_suite = {
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.name = "mean and variance tests",
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.test_cases = mean_and_variance_test_cases
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};
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kunit_test_suite(mean_and_variance_test_suite);
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MODULE_AUTHOR("Daniel B. Hill");
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MODULE_LICENSE("GPL");
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