Goroutine is cheap, but not free. Especially when the goroutine trigger runtime.morestack, the cost become high.

This package is mainly aimed to handle that. Put back the stack-growed goroutine to a pool, and reuse that goroutine can eliminate the runtime.morestack cost.

See a blog post (Chinese) https://www.zenlife.tk/goroutine-pool.md

Just replace your go f() call with gp.Go(f):

import "github.com/tiancaiamao/gp"

var gP = gp.New(N, time.Duration)

gp.Go(func() {
	// ...
})