Benchmarked: The state of Rust web frameworks in 2021

I benchmarked wrong, and these benchmarks are misleading, as my custom bencher bottlenecked. I will update this article with better benchmarks later

There's many web frameworks for Rust. actix-web, warp, rocket, oh my! They all have their distinct ups and downs, but usually actix-web is known as the fastest (albeit not without controversy), and rocket as one of the more user-friendly frameworks.

There's been various benchmarks throughout the years, but how do they all stand in 2021, with tokio 1.0 out?

Today, we're going to be testing 3 separate web frameworks. This is nowhere near all of them, but these are likely the most popular ones, and also ones I know enough about to try to avoid inexperience bias:

The reason these are all master is that the latest versions with Tokio 1.0 support have not been released fully yet.

In addition, we're going to try to maximize optimization during these rounds: We're going to use snmalloc as our global allocator, to try to minimize allocator overhead, and turning on optimization parameters in Cargo.toml

[profile.release]
opt-level = 3
codegen-units = 1
lto = true

[profile.release.package.'*']
opt-level = 3
codegen-units = 1

The Setup

Here's the various benchmarks we're going to run:

"Hello World" GET request (just returns a static string)
JSON GET request (returns JSON containing many different types)
JSON POST number sorting (POSTs a JSON-serialized array of numbers, and returns a sorted array)
JSON complex POST request (POSTs a rather complex JSON object, and returns one of the things from it)

Our "complex" JSON object is this mouthful of a type:

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExampleReturn {
	pub a: String,
	pub b: u32,
	pub c: u64,
	pub d: f32,
	pub e: f64,
	pub f: Vec<u64>,
	pub g: Vec<f64>,
	pub h: Vec<String>,
	pub j: BTreeMap<String, u64>,
}

Relevant system info:

Intel Core i7 8086k, overclocked to 5.1 Ghz
32GB DDR4 RAM
The tests were run inside of Arch Linux in WSL2, running the Linux 5.10.7-111-tkg-upds kernel.
rustc 1.49.0 (e1884a8e3 2020-12-29)

The source code for these benchmarks are on my Github, licensed under the BSD-3-Clause license.

There's not much more to explain, so let's get to the point (and probably the only reason you're reading this), the results!

The Results

`GET /hello`

	requests/second	average time	min time	max time
actix-web	8415.98	118µs	66µs	15ms
rocket	8230.11	121µs	67µs	8ms
warp	8293.88	120µs	60µs	15ms

`GET /json`

	requests/second	average time	min time	max time
actix-web	8481.12	117µs	66µs	12ms
rocket	8563.68	116µs	67µs	12ms
warp	8671.42	114µs	67µs	5ms

`POST /json-sort`

	requests/second	average time	min time	max time
actix-web	7333.80	136µs	78µs	14ms
rocket	7597.79	131µs	75µs	11ms
warp	7640.58	130µs	75µs	10ms

`POST /json-complex`

	requests/second	average time	min time	max time
actix-web	7471.30	133µs	71µs	13ms
rocket	7802.98	127µs	72µs	12ms
warp	7576.59	130µs	73µs	13ms

Latency

	average request latency	max request latency
actix-web	55µs	6ms
rocket	57µs	7ms
warp	52µs	2ms

min request latency is not here due to the fact it was broken

	average response latency	min response latency	max response latency
actix-web	68µs	21µs	4ms
rocket	70µs	25µs	10ms
warp	63µs	26µs	3ms

	average round-trip latency	min round-trip latency	max round-trip latency
actix-web	124µs	62µs	7ms
rocket	128µs	60µs	11ms
warp	116µs	69µs	4ms

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