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/*
* This file is open source software, licensed to you under the terms
* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
* distributed with this work for additional information regarding copyright
* ownership. You may not use this file except in compliance with the License.
*
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/*
* Copyright (C) 2015 Cloudius Systems, Ltd.
*
* To compile: g++ -std=c++14 slab_test.cc
*/
#include <iostream>
#include <assert.h>
#include <seastar/core/slab.hh>
using namespace seastar;
namespace bi = boost::intrusive;
static constexpr size_t max_object_size = 1024*1024;
class item : public slab_item_base {
public:
bi::list_member_hook<> _cache_link;
uint32_t _slab_page_index;
item(uint32_t slab_page_index) : _slab_page_index(slab_page_index) {}
const uint32_t get_slab_page_index() {
return _slab_page_index;
}
const bool is_unlocked() {
return true;
}
};
template<typename Item>
static void free_vector(slab_allocator<Item>& slab, std::vector<item *>& items) {
for (auto item : items) {
slab.free(item);
}
}
static void test_allocation_1(const double growth_factor, const unsigned slab_limit_size) {
slab_allocator<item> slab(growth_factor, slab_limit_size, max_object_size);
size_t size = max_object_size;
slab.print_slab_classes();
std::vector<item *> items;
assert(slab_limit_size % size == 0);
for (auto i = 0u; i < (slab_limit_size / size); i++) {
auto item = slab.create(size);
items.push_back(item);
}
assert(slab.create(size) == nullptr);
free_vector<item>(slab, items);
std::cout << __FUNCTION__ << " done!\n";
}
static void test_allocation_2(const double growth_factor, const unsigned slab_limit_size) {
slab_allocator<item> slab(growth_factor, slab_limit_size, max_object_size);
size_t size = 1024;
std::vector<item *> items;
auto allocations = 0u;
for (;;) {
auto item = slab.create(size);
if (!item) {
break;
}
items.push_back(item);
allocations++;
}
auto class_size = slab.class_size(size);
auto per_slab_page = max_object_size / class_size;
auto available_slab_pages = slab_limit_size / max_object_size;
assert(allocations == (per_slab_page * available_slab_pages));
free_vector<item>(slab, items);
std::cout << __FUNCTION__ << " done!\n";
}
static void test_allocation_with_lru(const double growth_factor, const unsigned slab_limit_size) {
bi::list<item, bi::member_hook<item, bi::list_member_hook<>, &item::_cache_link>> _cache;
unsigned evictions = 0;
slab_allocator<item> slab(growth_factor, slab_limit_size, max_object_size,
[&](item& item_ref) { _cache.erase(_cache.iterator_to(item_ref)); evictions++; });
size_t size = max_object_size;
auto max = slab_limit_size / max_object_size;
for (auto i = 0u; i < max * 1000; i++) {
auto item = slab.create(size);
assert(item != nullptr);
_cache.push_front(*item);
}
assert(evictions == max * 999);
_cache.clear();
std::cout << __FUNCTION__ << " done!\n";
}
int main(int ac, char** av) {
test_allocation_1(1.25, 5*1024*1024);
test_allocation_2(1.07, 5*1024*1024); // 1.07 is the growth factor used by facebook.
test_allocation_with_lru(1.25, 5*1024*1024);
return 0;
}
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