https://github.com/npavlinek/memory_allocation_experiment

https://github.com/npavlinek/memory_allocation_experiment

Last synced: about 1 month ago
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• Host: GitHub
• URL: https://github.com/npavlinek/memory_allocation_experiment
• Owner: npavlinek
• License: 0bsd
• Created: 2023-04-10T19:06:25.000Z (almost 2 years ago)
• Default Branch: master
• Last Pushed: 2023-07-11T15:23:10.000Z (over 1 year ago)
• Last Synced: 2024-10-26T22:31:44.797Z (3 months ago)
• Language: C++
• Size: 20.5 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Memory Allocation Experiment

## About

The experiment was to see whether it is worth it to implement and use a custom memory allocator for performance and code simplicity.

There are three different implementations:

- STL version: using `std::string` and `std::vector`, a fairly standard implementation

- Non-STL version: using only `malloc`, a custom string builder and storing file names as a linked list

- Custom allocator version: the same as the non-STL version, but using a custom linear allocator

The implementations recursively iterate over all files and directories inside of the current directory, saving all file names into memory.

## Results

Running this program inside the Mozilla source code repository (changeset `66e3220110ba0dd99ba7d45684ac4731886a59a9`):

```

STL version took 5.09 s and found 1062892 items

Non-STL version took 4.13 s and found 1062892 items

Custom allocator version took 4.09 s and found 1062892 items

```

In this case the custom allocator version is slightly faster, sometimes it is even faster and other times it is slower than the non-STL version. I still see this as a win though. Even if the custom allocator breaks even with `malloc`, it is still a win because of its' simplicity; the custom allocator is 19 lines of code (depending on how you count code), there is no way `malloc` is anywhere close to that.

## License

Zero Clause BSD License, a public domain equivalent license. See the `LICENSE` file for more details.