Go: runtime: >200ms GC latency in test programs (calling runtime.GC?)

Created on 26 May 2016 · 42Comments · Source: golang/go

What version of Go are you using (go version)?
go version go1.6.2 windows/amd64
What operating system and processor architecture are you using (go env)?
set GOARCH=amd64
set GOBIN=
set GOEXE=.exe
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:dev\Go
set GORACE=
set GOROOT=C:\Go
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GO15VENDOREXPERIMENT=1
set CC=gcc
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0
set CXX=g++
set CGO_ENABLED=1
What did you do?
Hello, I am writing a POC software that should replace a currently running C application.
The server part loads a SQLITE db3 file in memory (using maps) and then waits for text commands on UDP socket.

The client reads a text file with commands, sends them to the server and waits for a response.
The client takes measurement on server reply time.

My tests were taken on the same machine (localhost) to avoid network delays

While running the client, response time jumps from 3 milliseconds to more than 200 milliseconds
and in the same moment the server displays this line (I am running it with SET GODEBUG=gctrace=1)

gc 14 @18.400s 2%: 0.50+380+1.0 ms clock, 2.0+294/380/266+4.0 ms cpu, 344->344->182 MB, 359 MB goal, 4 P

I think that 200ms STW is a bit too much and would like to know how to fix this beahvior
I have a dropbox folder with server and client sources, and corresponding SQLITE DB and command text file
(https://www.dropbox.com/sh/e2timsyjifvp61i/AAAmDoKSP7NANjDlsYcGcBvGa?dl=0)

the client must be executed with 2 parameters: