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rocksdb/util/arena_test.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/arena.h"
#include "util/random.h"
#include "util/testharness.h"
namespace rocksdb {
class ArenaTest {};
TEST(ArenaTest, Empty) { Arena arena0; }
TEST(ArenaTest, MemoryAllocatedBytes) {
const int N = 17;
size_t req_sz; // requested size
size_t bsz = 8192; // block size
size_t expected_memory_allocated;
Arena arena(bsz);
// requested size > quarter of a block:
// allocate requested size separately
req_sz = 3001;
for (int i = 0; i < N; i++) {
arena.Allocate(req_sz);
}
expected_memory_allocated = req_sz * N;
ASSERT_EQ(arena.MemoryAllocatedBytes(), expected_memory_allocated);
// requested size < quarter of a block:
// allocate a block with the default size, then try to use unused part
// of the block. So one new block will be allocated for the first
// Allocate(99) call. All the remaining calls won't lead to new allocation.
req_sz = 99;
for (int i = 0; i < N; i++) {
arena.Allocate(req_sz);
}
expected_memory_allocated += bsz;
ASSERT_EQ(arena.MemoryAllocatedBytes(), expected_memory_allocated);
// requested size > quarter of a block:
// allocate requested size separately
req_sz = 99999999;
for (int i = 0; i < N; i++) {
arena.Allocate(req_sz);
}
expected_memory_allocated += req_sz * N;
ASSERT_EQ(arena.MemoryAllocatedBytes(), expected_memory_allocated);
}
// Make sure we didn't count the allocate but not used memory space in
// Arena::ApproximateMemoryUsage()
TEST(ArenaTest, ApproximateMemoryUsageTest) {
const size_t kBlockSize = 4096;
const size_t kEntrySize = kBlockSize / 8;
const size_t kZero = 0;
Arena arena(kBlockSize);
ASSERT_EQ(kZero, arena.ApproximateMemoryUsage());
auto num_blocks = kBlockSize / kEntrySize;
// first allocation
arena.AllocateAligned(kEntrySize);
auto mem_usage = arena.MemoryAllocatedBytes();
ASSERT_EQ(mem_usage, kBlockSize);
auto usage = arena.ApproximateMemoryUsage();
ASSERT_LT(usage, mem_usage);
for (size_t i = 1; i < num_blocks; ++i) {
arena.AllocateAligned(kEntrySize);
ASSERT_EQ(mem_usage, arena.MemoryAllocatedBytes());
ASSERT_EQ(arena.ApproximateMemoryUsage(), usage + kEntrySize);
usage = arena.ApproximateMemoryUsage();
}
ASSERT_GT(usage, mem_usage);
}
TEST(ArenaTest, Simple) {
std::vector<std::pair<size_t, char*>> allocated;
Arena arena;
const int N = 100000;
size_t bytes = 0;
Random rnd(301);
for (int i = 0; i < N; i++) {
size_t s;
if (i % (N / 10) == 0) {
s = i;
} else {
s = rnd.OneIn(4000)
? rnd.Uniform(6000)
: (rnd.OneIn(10) ? rnd.Uniform(100) : rnd.Uniform(20));
}
if (s == 0) {
// Our arena disallows size 0 allocations.
s = 1;
}
char* r;
if (rnd.OneIn(10)) {
r = arena.AllocateAligned(s);
} else {
r = arena.Allocate(s);
}
for (unsigned int b = 0; b < s; b++) {
// Fill the "i"th allocation with a known bit pattern
r[b] = i % 256;
}
bytes += s;
allocated.push_back(std::make_pair(s, r));
ASSERT_GE(arena.ApproximateMemoryUsage(), bytes);
if (i > N / 10) {
ASSERT_LE(arena.ApproximateMemoryUsage(), bytes * 1.10);
}
}
for (unsigned int i = 0; i < allocated.size(); i++) {
size_t num_bytes = allocated[i].first;
const char* p = allocated[i].second;
for (unsigned int b = 0; b < num_bytes; b++) {
// Check the "i"th allocation for the known bit pattern
ASSERT_EQ(int(p[b]) & 0xff, (int)(i % 256));
}
}
}
} // namespace rocksdb
int main(int argc, char** argv) { return rocksdb::test::RunAllTests(); }