In this week’s class I explained what memory pools are and how to use them to optimize frequent allocations and deallocations of objects. I also demonstrated how to overwrite
operator new /
operator new [] and
operator delete /
operator delete [] for a
struct /
class type.
The code for this class contains a simple benchmark which measures pool’s performance against the general-purpose allocator in C++ runtime. Notice how multi-threaded benchmark causes the pool to perform poorly (I suspect due to lock contention, though I did not yet investigate this). I didn’t even bother measuring array allocations; the memory pool benchmark causes massive fragmentation of the free chunks (by allocating all available chunks, shuffling them randomly, then freeing all) making continuous allocations virtually impossible without falling back onto runtime allocator.
Next week I plan on actually implementing a simple memory pool then again measure its performance against the runtime. Enjoy the video!
P.S. Remember to pick HD version of the video. It is also best to watch in full screen mode due to the font size used. I will try to remember to increase it during my next class. Apologies to anyone finding it hard to read the code.
Code from the class:
lesson_pool_allocator.cpp | lesson_pool_allocator_benchmark.cpp
One Reply to “How to use memory pools”