Edata cache small: rewrite.

In previous designs, this was intended to be a sort of cache that couldn't fail.
In the current design, we want to use it just as a contention reduction
mechanism.  Rewrite it with those goals in mind.
This commit is contained in:
David Goldblatt
2020-10-29 05:11:16 -07:00
committed by David Goldblatt
parent c9757d9e3b
commit 03a6047111
3 changed files with 302 additions and 77 deletions

View File

@@ -47,37 +47,198 @@ TEST_BEGIN(test_edata_cache) {
}
TEST_END
TEST_BEGIN(test_edata_cache_small) {
TEST_BEGIN(test_edata_cache_small_simple) {
edata_cache_t ec;
edata_cache_small_t ecs;
test_edata_cache_init(&ec);
edata_cache_small_init(&ecs, &ec);
bool err = edata_cache_small_prepare(TSDN_NULL, &ecs, 2);
assert_false(err, "");
assert_zu_eq(ecs.count, 2, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_t *ed1 = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(ed1, "");
expect_zu_eq(ecs.count, 0, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_t *ed1 = edata_cache_small_get(&ecs);
assert_zu_eq(ecs.count, 1, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_t *ed2 = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(ed2, "");
expect_zu_eq(ecs.count, 0, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_t *ed2 = edata_cache_small_get(&ecs);
assert_zu_eq(ecs.count, 0, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_cache_small_put(TSDN_NULL, &ecs, ed1);
expect_zu_eq(ecs.count, 1, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_cache_small_put(&ecs, ed1);
assert_zu_eq(ecs.count, 1, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_cache_small_put(TSDN_NULL, &ecs, ed2);
expect_zu_eq(ecs.count, 2, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_cache_small_put(&ecs, ed2);
assert_zu_eq(ecs.count, 2, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
/* LIFO ordering. */
expect_ptr_eq(ed2, edata_cache_small_get(TSDN_NULL, &ecs), "");
expect_zu_eq(ecs.count, 1, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
edata_cache_small_finish(TSDN_NULL, &ecs, 1);
assert_zu_eq(ecs.count, 1, "");
assert_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 1, "");
expect_ptr_eq(ed1, edata_cache_small_get(TSDN_NULL, &ecs), "");
expect_zu_eq(ecs.count, 0, "");
expect_zu_eq(atomic_load_zu(&ec.count, ATOMIC_RELAXED), 0, "");
test_edata_cache_destroy(&ec);
}
TEST_END
TEST_BEGIN(test_edata_cache_fill) {
edata_cache_t ec;
edata_cache_small_t ecs;
test_edata_cache_init(&ec);
edata_cache_small_init(&ecs, &ec);
edata_t *allocs[EDATA_CACHE_SMALL_FILL * 2];
/*
* If the fallback cache can't satisfy the request, we shouldn't do
* extra allocations until compelled to. Put half the fill goal in the
* fallback.
*/
for (int i = 0; i < EDATA_CACHE_SMALL_FILL / 2; i++) {
allocs[i] = edata_cache_get(TSDN_NULL, &ec);
}
for (int i = 0; i < EDATA_CACHE_SMALL_FILL / 2; i++) {
edata_cache_put(TSDN_NULL, &ec, allocs[i]);
}
expect_zu_eq(EDATA_CACHE_SMALL_FILL / 2,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
allocs[0] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_zu_eq(EDATA_CACHE_SMALL_FILL / 2 - 1, ecs.count,
"Should have grabbed all edatas available but no more.");
for (int i = 1; i < EDATA_CACHE_SMALL_FILL / 2; i++) {
allocs[i] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(allocs[i], "");
}
expect_zu_eq(0, ecs.count, "");
/* When forced, we should alloc from the base. */
edata_t *edata = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(edata, "");
expect_zu_eq(0, ecs.count, "Allocated more than necessary");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED),
"Allocated more than necessary");
/*
* We should correctly fill in the common case where the fallback isn't
* exhausted, too.
*/
for (int i = 0; i < EDATA_CACHE_SMALL_FILL * 2; i++) {
allocs[i] = edata_cache_get(TSDN_NULL, &ec);
expect_ptr_not_null(allocs[i], "");
}
for (int i = 0; i < EDATA_CACHE_SMALL_FILL * 2; i++) {
edata_cache_put(TSDN_NULL, &ec, allocs[i]);
}
allocs[0] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_zu_eq(EDATA_CACHE_SMALL_FILL - 1, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
for (int i = 1; i < EDATA_CACHE_SMALL_FILL; i++) {
expect_zu_eq(EDATA_CACHE_SMALL_FILL - i, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
allocs[i] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(allocs[i], "");
}
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
allocs[0] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_zu_eq(EDATA_CACHE_SMALL_FILL - 1, ecs.count, "");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
for (int i = 1; i < EDATA_CACHE_SMALL_FILL; i++) {
expect_zu_eq(EDATA_CACHE_SMALL_FILL - i, ecs.count, "");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
allocs[i] = edata_cache_small_get(TSDN_NULL, &ecs);
expect_ptr_not_null(allocs[i], "");
}
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
test_edata_cache_destroy(&ec);
}
TEST_END
TEST_BEGIN(test_edata_cache_flush) {
edata_cache_t ec;
edata_cache_small_t ecs;
test_edata_cache_init(&ec);
edata_cache_small_init(&ecs, &ec);
edata_t *allocs[2 * EDATA_CACHE_SMALL_MAX + 2];
for (int i = 0; i < 2 * EDATA_CACHE_SMALL_MAX + 2; i++) {
allocs[i] = edata_cache_get(TSDN_NULL, &ec);
expect_ptr_not_null(allocs[i], "");
}
for (int i = 0; i < EDATA_CACHE_SMALL_MAX; i++) {
edata_cache_small_put(TSDN_NULL, &ecs, allocs[i]);
expect_zu_eq(i + 1, ecs.count, "");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
}
edata_cache_small_put(TSDN_NULL, &ecs, allocs[EDATA_CACHE_SMALL_MAX]);
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_MAX + 1,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
for (int i = EDATA_CACHE_SMALL_MAX + 1;
i < 2 * EDATA_CACHE_SMALL_MAX + 1; i++) {
edata_cache_small_put(TSDN_NULL, &ecs, allocs[i]);
expect_zu_eq(i - EDATA_CACHE_SMALL_MAX, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_MAX + 1,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
}
edata_cache_small_put(TSDN_NULL, &ecs, allocs[2 * EDATA_CACHE_SMALL_MAX + 1]);
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(2 * EDATA_CACHE_SMALL_MAX + 2,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
test_edata_cache_destroy(&ec);
}
TEST_END
TEST_BEGIN(test_edata_cache_disable) {
edata_cache_t ec;
edata_cache_small_t ecs;
test_edata_cache_init(&ec);
edata_cache_small_init(&ecs, &ec);
for (int i = 0; i < EDATA_CACHE_SMALL_FILL; i++) {
edata_t *edata = edata_cache_get(TSDN_NULL, &ec);
expect_ptr_not_null(edata, "");
edata_cache_small_put(TSDN_NULL, &ecs, edata);
}
expect_zu_eq(EDATA_CACHE_SMALL_FILL, ecs.count, "");
expect_zu_eq(0, atomic_load_zu(&ec.count, ATOMIC_RELAXED), "");
edata_cache_small_disable(TSDN_NULL, &ecs);
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL,
atomic_load_zu(&ec.count, ATOMIC_RELAXED), "Disabling should flush");
edata_t *edata = edata_cache_small_get(TSDN_NULL, &ecs);
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL - 1,
atomic_load_zu(&ec.count, ATOMIC_RELAXED),
"Disabled ecs should forward on get");
edata_cache_small_put(TSDN_NULL, &ecs, edata);
expect_zu_eq(0, ecs.count, "");
expect_zu_eq(EDATA_CACHE_SMALL_FILL,
atomic_load_zu(&ec.count, ATOMIC_RELAXED),
"Disabled ecs should forward on put");
test_edata_cache_destroy(&ec);
}
@@ -87,5 +248,8 @@ int
main(void) {
return test(
test_edata_cache,
test_edata_cache_small);
test_edata_cache_small_simple,
test_edata_cache_fill,
test_edata_cache_flush,
test_edata_cache_disable);
}