This app contains two APIs.
Both of them will serve a static file from disk.
http://localhost:8080/1 will do it by openning the file, reading it and setting it as body.
http://localhost:8080/2 will do it by using fasthttp.ServeFile function.
There are also two images in this repo. image1.jpg and image2.jpg.
When servering image1.jpg, fasthttp.ServeFile is much slower.
> go-wrk -d 3 "http://localhost:8080/1"
Running 3s test @ http://localhost:8080/1
10 goroutine(s) running concurrently
31200 requests in 2.923608791s, 1.46GB read
Requests/sec: 10671.74
Transfer/sec: 512.34MB
Avg Req Time: 937.054µs
Fastest Request: 134.841µs
Slowest Request: 7.879186ms
Number of Errors: 0
==========================================
> go-wrk -d 3 "http://localhost:8080/2"
Running 3s test @ http://localhost:8080/2
10 goroutine(s) running concurrently
248 requests in 3.029993142s, 11.92MB read
Requests/sec: 81.85
Transfer/sec: 3.93MB
Avg Req Time: 122.177142ms
Fastest Request: 118.257µs
Slowest Request: 216.498781ms
Number of Errors: 0
But amazingly when you change image_path variable in code to image2.jpg
Results are relatively close. I cannot understand what is happening.
I've tried to use pprof but I don't know why it does not generate cpu profile
for fasthttp api.