Go 1.3 Garbage collector not releasing server memory back to system

Question

We wrote the simplest possible TCP server (with minor logging) to examine the memory footprint (see tcp-server.go below)

The server simply accepts connections and do

Answer 1

As Jsor said, you should wait at least 7 minutes to check how much memory is freed. Sometimes it needs two GC passes, so it would be 9 minutes.

If that is not working, or it is too much time, you can add a periodic call to FreeOSMemory (no need to call runtime.GC() before, it is done by debug.FreeOSMemory() )

Something like this: http://play.golang.org/p/mP7_sMpX4F

package main

import (
    "runtime/debug"
    "time"
)

func main() {
    go periodicFree(1 * time.Minute)

    // Your program goes here

}

func periodicFree(d time.Duration) {
    tick := time.Tick(d)
    for _ = range tick {
        debug.FreeOSMemory()
    }
}

Take into account that every call to FreeOSMemory will take some time (not much) and it can be partly run in parallel if GOMAXPROCS>1 since Go1.3.