如何提升 FastAPI 的 RPS 上限

这是我在网站目录下放了返回数据样本(不到 1k)，直接通过 Nginx （ 4 个 workers ）返回静态文件的压测结果

wrk -t2 -c750 -d10s https://xxx.com/test.json
Running 10s test @ https://xxx.com/test.json
  2 threads and 750 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    39.13ms   61.57ms 793.10ms   96.90%
    Req/Sec    11.84k     1.88k   16.28k    80.46%
  211719 requests in 10.09s, 140.73MB read
Requests/sec:  20989.41
Transfer/sec:     13.95MB

于是我又打算测试下裸连 Gunicorn （也是 4 个 workers ），请求一个不到 1k 的 1x1 透明 gif gunicorn -k uvicorn.workers.UvicornWorker -w 4 -b 127.0.0.1:8000 main:app

TRANSPARENT_GIF = (
    b"\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00"
    b"\xff\xff\xff\x21\xf9\x04\x01\x00\x00\x00\x00\x2c\x00\x00\x00\x00"
    b"\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3b"
)

@app.get("/api/ping.gif")
def transparent_image():
    return Response(content=TRANSPARENT_GIF, media_type="image/gif")

wrk -t2 -c750 -d10s http://127.0.0.1:8000/api/ping.gif
Running 10s test @ http://127.0.0.1:8000/api/ping.gif
  2 threads and 750 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   440.03ms  189.73ms 979.84ms   59.90%
    Req/Sec   846.07    359.59     1.65k    65.13%
  16483 requests in 10.09s, 2.54MB read
Requests/sec:   1633.21
Transfer/sec:    257.37KB

Nginx 直接返回数据:20989.41 rps 不反向代理，裸连 Gunicorn:1633.21 rps

这性能差距也太大了吧？

dongruixuan

51 天前

简单测了下 rust ，用的 actix-web 。CPU i5-13600K, 在 WSL 下运行。RPS 1.38M
```shell
wrk -t8 -c750 -d10s http://127.0.0.1:8000/api/ping.gif
Running 10s test @ http://127.0.0.1:8000/api/ping.gif
8 threads and 750 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 535.49us 767.36us 14.77ms 90.42%
Req/Sec 175.31k 19.72k 209.16k 76.43%
13988354 requests in 10.10s, 2.11GB read
Requests/sec: 1384945.09
Transfer/sec: 213.97MB
```
如果 wrk 用 2 线程 750 连接只能打到
```
wrk -t2 -c750 -d10s http://127.0.0.1:8000/api/ping.gif
Running 10s test @ http://127.0.0.1:8000/api/ping.gif
2 threads and 750 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 2.05ms 0.98ms 10.72ms 59.25%
Req/Sec 92.84k 3.88k 98.45k 85.86%
1851767 requests in 10.10s, 286.09MB read
Requests/sec: 183347.71
Transfer/sec: 28.33MB
```
代码如下
```rust
use actix_web;
use actix_web::{get, App, HttpResponse, HttpServer, Responder};

const TRANSPARENT_GIF: &'static [u8] =
b"\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00
\xff\xff\xff\x21\xf9\x04\x01\x00\x00\x00\x00\x2c\x00\x00\x00\x00
\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3b";

#[get("/api/ping.gif")]
async fn transparent_image() -> impl Responder {
HttpResponse::Ok()
.append_header(("Content-Type", "image/gif"))
.body(TRANSPARENT_GIF)
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
HttpServer::new(|| {
App::new()
.service(transparent_image)
})
.bind(("127.0.0.1", 8000))?
.run()
.await
}
```