/**************************************************************************/
/* test_rid.h */
/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
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#ifndef TEST_RID_H
#define TEST_RID_H
#include "core/os/thread.h"
#include "core/templates/local_vector.h"
#include "core/templates/rid.h"
#include "core/templates/rid_owner.h"
#include "tests/test_macros.h"
#ifdef SANITIZERS_ENABLED
#ifdef __has_feature
#if __has_feature(thread_sanitizer)
#define TSAN_ENABLED
#endif
#elif defined(__SANITIZE_THREAD__)
#define TSAN_ENABLED
#endif
#endif
#ifdef TSAN_ENABLED
#include <sanitizer/tsan_interface.h>
#endif
namespace TestRID {
TEST_CASE("[RID] Default Constructor") {
RID rid;
CHECK(rid.get_id() == 0);
}
TEST_CASE("[RID] Factory method") {
RID rid = RID::from_uint64(1);
CHECK(rid.get_id() == 1);
}
TEST_CASE("[RID] Operators") {
RID rid = RID::from_uint64(1);
RID rid_zero = RID::from_uint64(0);
RID rid_one = RID::from_uint64(1);
RID rid_two = RID::from_uint64(2);
CHECK_FALSE(rid == rid_zero);
CHECK(rid == rid_one);
CHECK_FALSE(rid == rid_two);
CHECK_FALSE(rid < rid_zero);
CHECK_FALSE(rid < rid_one);
CHECK(rid < rid_two);
CHECK_FALSE(rid <= rid_zero);
CHECK(rid <= rid_one);
CHECK(rid <= rid_two);
CHECK(rid > rid_zero);
CHECK_FALSE(rid > rid_one);
CHECK_FALSE(rid > rid_two);
CHECK(rid >= rid_zero);
CHECK(rid >= rid_one);
CHECK_FALSE(rid >= rid_two);
CHECK(rid != rid_zero);
CHECK_FALSE(rid != rid_one);
CHECK(rid != rid_two);
}
TEST_CASE("[RID] 'is_valid' & 'is_null'") {
RID rid_zero = RID::from_uint64(0);
RID rid_one = RID::from_uint64(1);
CHECK_FALSE(rid_zero.is_valid());
CHECK(rid_zero.is_null());
CHECK(rid_one.is_valid());
CHECK_FALSE(rid_one.is_null());
}
TEST_CASE("[RID] 'get_local_index'") {
CHECK(RID::from_uint64(1).get_local_index() == 1);
CHECK(RID::from_uint64(4'294'967'295).get_local_index() == 4'294'967'295);
CHECK(RID::from_uint64(4'294'967'297).get_local_index() == 1);
}
// This case would let sanitizers realize data races.
// Additionally, on purely weakly ordered architectures, it would detect synchronization issues
// if RID_Alloc failed to impose proper memory ordering and the test's threads are distributed
// among multiple L1 caches.
TEST_CASE("[RID_Owner] Thread safety") {
struct DataHolder {
char data[Thread::CACHE_LINE_BYTES];
};
struct RID_OwnerTester {
uint32_t thread_count = 0;
RID_Owner<DataHolder, true> rid_owner;
TightLocalVector<Thread> threads;
SafeNumeric<uint32_t> next_thread_idx;
// Using std::atomic directly since SafeNumeric doesn't support relaxed ordering.
TightLocalVector<std::atomic<uint64_t>> rids;
std::atomic<uint32_t> sync[2] = {};
std::atomic<uint32_t> correct = 0;
// A barrier that doesn't introduce memory ordering constraints, only compiler ones.
// The idea is not to cause any sync traffic that would make the code we want to test
// seem correct as a side effect.
void lockstep(uint32_t p_step) {
uint32_t buf_idx = p_step % 2;
uint32_t target = (p_step / 2 + 1) * threads.size();
sync[buf_idx].fetch_add(1, std::memory_order_relaxed);
do {
std::this_thread::yield();
} while (sync[buf_idx].load(std::memory_order_relaxed) != target);
}
explicit RID_OwnerTester(bool p_chunk_for_all, bool p_chunks_preallocated) :
thread_count(OS::get_singleton()->get_processor_count()),
rid_owner(sizeof(DataHolder) * (p_chunk_for_all ? thread_count : 1)) {
threads.resize(thread_count);
rids.resize(threads.size());
if (p_chunks_preallocated) {
LocalVector<RID> prealloc_rids;
for (uint32_t i = 0; i < (p_chunk_for_all ? 1 : threads.size()); i++) {
prealloc_rids.push_back(rid_owner.make_rid());
}
for (uint32_t i = 0; i < prealloc_rids.size(); i++) {
rid_owner.free(prealloc_rids[i]);
}
}
}
~RID_OwnerTester() {
for (uint32_t i = 0; i < threads.size(); i++) {
rid_owner.free(RID::from_uint64(rids[i].load(std::memory_order_relaxed)));
}
}
void test() {
for (uint32_t i = 0; i < threads.size(); i++) {
threads[i].start(
[](void *p_data) {
RID_OwnerTester *rot = (RID_OwnerTester *)p_data;
auto _compute_thread_unique_byte = [](uint32_t p_idx) -> char {
return ((p_idx & 0xff) ^ (0b11111110 << (p_idx % 8)));
};
// 1. Each thread gets a zero-based index.
uint32_t self_th_idx = rot->next_thread_idx.postincrement();
rot->lockstep(0);
// 2. Each thread makes a RID holding unique data.
DataHolder initial_data;
memset(&initial_data, _compute_thread_unique_byte(self_th_idx), Thread::CACHE_LINE_BYTES);
RID my_rid = rot->rid_owner.make_rid(initial_data);
rot->rids[self_th_idx].store(my_rid.get_id(), std::memory_order_relaxed);
rot->lockstep(1);
// 3. Each thread verifies all the others.
uint32_t local_correct = 0;
for (uint32_t th_idx = 0; th_idx < rot->threads.size(); th_idx++) {
if (th_idx == self_th_idx) {
continue;
}
char expected_unique_byte = _compute_thread_unique_byte(th_idx);
RID rid = RID::from_uint64(rot->rids[th_idx].load(std::memory_order_relaxed));
DataHolder *data = rot->rid_owner.get_or_null(rid);
#ifdef TSAN_ENABLED
__tsan_acquire(data); // We know not a race in practice.
#endif
bool ok = true;
for (uint32_t j = 0; j < Thread::CACHE_LINE_BYTES; j++) {
if (data->data[j] != expected_unique_byte) {
ok = false;
break;
}
}
if (ok) {
local_correct++;
}
#ifdef TSAN_ENABLED
__tsan_release(data);
#endif
}
rot->lockstep(2);
rot->correct.fetch_add(local_correct, std::memory_order_acq_rel);
},
this);
}
for (uint32_t i = 0; i < threads.size(); i++) {
threads[i].wait_to_finish();
}
CHECK_EQ(correct.load(), threads.size() * (threads.size() - 1));
}
};
SUBCASE("All items in one chunk, pre-allocated") {
RID_OwnerTester tester(true, true);
tester.test();
}
SUBCASE("All items in one chunk, NOT pre-allocated") {
RID_OwnerTester tester(true, false);
tester.test();
}
SUBCASE("One item per chunk, pre-allocated") {
RID_OwnerTester tester(false, true);
tester.test();
}
SUBCASE("One item per chunk, NOT pre-allocated") {
RID_OwnerTester tester(false, false);
tester.test();
}
}
} // namespace TestRID
#endif // TEST_RID_H