Memory allocation problem


I profiled by my program by tracking user memory allocation. The program seems to incur memory allocation at places I don’t expect.

My program is pretty long so I have it updated to Github:

There is also the memory tracking output and a sample dataset.

The function that I am trying to optimize is sample_one_word which is currently the bottleneck of my program.

Mainly I don’t understand why memory allocations happen when the program reads and writes a single element of a Vector, for example, see line 178, line 272, line 278, etc.

This program is about 2~3X slower than a C++ implementation and I am suspecting memory allocation is one main bottleneck.


This naively looks like a type stability issue. Can you update your code to generate random test-data first, so that we can copy-paste it into the REPL?


Have you precompiled your code first? That line 178 seems like compilation allocation. Note that the allocation printed some times is off a line…


Thanks! I’ve added a program that generates random input:


Thanks for your answer!

No, I didn’t precompile my code. The sample_one_word function is executed hundreds of thousands of times, but it’s JIT compiled just one. It would be pretty shocking that compiling one function allocates 480MB of memory, right?


Looking at @code_warntype, I see that new_topic in sample_all_words is not inferred and sample_one_word has an Int32/Int64 instability.


Thank you! This is very helpful!