bartmassey / sort-race

racing sorts in PHP and C

PHP Quicksort vs C Bubble Sort Throwdown

Copyright (c) 2019 Bart Massey

I borrowed a PHP implementation of Quicksort (quicksort.php) and wrote my own Bubble Sort in C (bubblesort.c) and comparable Rust (bubblesort.rs) so I could race 'em in response to a Reddit thread; (I also wrote a PHP Bubble Sort (bubblesort.php) just out of curiosity: it runs about 30× slower than PHP Quicksort.) Each implementation of Bubble Sort creates an array of the first n integers, shuffles it, and then sorts it back.

Turns out the breakeven on my box is about 5,000 elements: that is the size at which the PHP Quicksort, the C Bubble Sort compiled with GCC and the Rust Bubble Sort take about 0.012 seconds on my box. The output of the benchmark run shows compiler/interpreter versions and timing.

I timed both the simple and in-place PHP Quicksort: at this size they both run in about the same time. This suggests that PHP's startup overhead is a limiting factor: I wrote a Rust Quicksort transliterated directly from the PHP in-place quicksort, and raced them on 1M elements to get a fairer speed comparison. At this scale PHP is about 8× slower than Rust for Quicksort, which is actually pretty impressive.

C Bubble Sort compiled with Clang is about twice as fast: I suspect it has figured out that it doesn't have to do the whole sort since it only is printing the first element. Meh.

The standalone Rust Bubble Sort was a pain, since the Rust Standard Library apparently has no built-in random-number support. This was super-annoying: I currently require an extra "seed" argument to this program.

License

"MIT". Please see the file LICENSE in this distribution for license terms.