Created
July 1, 2012 04:06
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Comparison of performance of adding elements to containers in C++
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Vector took 0.18 seconds. | |
Preallocated Vector took 0.1 seconds. | |
Back pushed List took 1.38 seconds. | |
Front pushed List took 1 seconds. | |
Front pushed Pool allocated list took 0.67 seconds. | |
In other words, | |
Preallocating a vector makes it ~200% faster than not preallocating | |
Pushing to the front makes it ~150% faster than pushing to the back | |
Pushing to the front and using a pool allocator makes it ~200% faster than pushing to the back |
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#include <vector> | |
#include <list> | |
#include <iostream> | |
#include <ctime> | |
#include <boost/pool/pool_alloc.hpp> | |
#define TEST_LIST_SIZE (10000000) | |
typedef boost::fast_pool_allocator< | |
int, | |
boost::default_user_allocator_new_delete, | |
boost::details::pool::default_mutex, | |
TEST_LIST_SIZE> BoostIntAllocator; | |
typedef boost::singleton_pool<boost::fast_pool_allocator_tag, sizeof(int)> BoostIntAllocatorPool; | |
void createMillionVector() | |
{ | |
std::vector<int> v; | |
for (int i = 0; i < TEST_LIST_SIZE; ++i) | |
{ | |
v.push_back(i); | |
} | |
} | |
void createPreallocatedMillionVector() | |
{ | |
std::vector<int> v; | |
v.reserve(TEST_LIST_SIZE); | |
for (int i = 0; i < TEST_LIST_SIZE; ++i) | |
{ | |
v.push_back(i); | |
} | |
} | |
void createMillionListBack() | |
{ | |
std::list<int> L; | |
for (int i = 0; i < TEST_LIST_SIZE; ++i) | |
{ | |
L.push_back(i); | |
} | |
} | |
void createMillionListFront() | |
{ | |
std::list<int> L; | |
for (int i = 0; i < TEST_LIST_SIZE; ++i) | |
{ | |
L.push_front(i); | |
} | |
} | |
void createPoolAllocatedMillionListFront() | |
{ | |
std::list<int, BoostIntAllocator> L; | |
for (int i = 0; i < TEST_LIST_SIZE; ++i) | |
{ | |
L.push_front(i); | |
} | |
BoostIntAllocatorPool::purge_memory(); | |
} | |
int main() | |
{ | |
clock_t preVectorTime = clock(); | |
createMillionVector(); | |
clock_t postVectorTime = clock(); | |
createPreallocatedMillionVector(); | |
clock_t postPreallocatedVectorTime = clock(); | |
createMillionListBack(); | |
clock_t postListBackTime = clock(); | |
createMillionListFront(); | |
clock_t postListFrontTime = clock(); | |
createPoolAllocatedMillionListFront(); | |
clock_t postPoolAllocatedListFrontTime = clock(); | |
std::cout << "Vector took " << (postVectorTime - preVectorTime) / (float)CLOCKS_PER_SEC << " seconds." << std::endl; | |
std::cout << "Preallocated Vector took " << (postPreallocatedVectorTime - postVectorTime) / (float)CLOCKS_PER_SEC << " seconds." << std::endl; | |
std::cout << "Back pushed List took " << (postListBackTime - postPreallocatedVectorTime) / (float)CLOCKS_PER_SEC << " seconds." << std::endl; | |
std::cout << "Front pushed List took " << (postListFrontTime - postListBackTime) / (float)CLOCKS_PER_SEC << " seconds." << std::endl; | |
std::cout << "Front pushed Pool allocated list took " << (postPoolAllocatedListFrontTime - postListFrontTime) / (float)CLOCKS_PER_SEC << " seconds." << std::endl; | |
} |
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