Top posts

Every blog post that took off on Hacker News, ranked by the votes of its best submission. 4,387 posts.

Systems & Performance
Any year
1142

What is malloc doing, anyway?

malloc has a very nice and simple interface: you ask for a certain amount of memory, and you’re given a void pointer to your block of contiguous bytes that’s been magicked into existence. Once you’re done with it, you call free with the same pointer and the memory disappears into the ether.

1149

The true cost of linked lists

Linked lists are often overused in introductory algorithmics courses, due to a heavy focus on theorical complexities. Unfortunatly, in practice, computers are complex beasts. They don’t execute instructions sequentially 1 with the same cost 2 . This means that a data structure with faster theorical complexities does…

1160

PHP 7's new hashtable implementation

About three years ago I wrote an article analyzing the memory usage of arrays in PHP 5. As part of the work on the upcoming PHP 7, large parts of the Zend Engine have been rewritten with a focus on smaller data structures requiring fewer allocations. In this article I will provide an overview of the new hashtable…

1162

Better Compression with Zstandard

I think I first heard about the Zstandard compression algorithm at a Mercurial developer sprint in 2015. At one end of a large table a few people were uttering expletives out of sheer excitement. At developer gatherings, that's the universal signal for something is awesome . Long story short, a Facebook engineer…