Time.sleep and Ticker bug in 1.16

[konethmelathil]

What version of Go are you using (go version)?

1.16

$ go version
I was using 1.16 and then switched back to 1.15.8 windows/amd64

This does not appear to be a issue in go version go1.16 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Windows 10 / amd64

go env Output

$ go env
Output generated after reverting back to 1.15.8:
set GO111MODULE=

set GOARCH=amd64

set GOBIN=

set GOCACHE=C:\Users\user1\AppData\Local\go-build

set GOENV=C:\Users\user1\AppData\Roaming\go\env

set GOEXE=.exe

set GOFLAGS=

set GOHOSTARCH=amd64

set GOHOSTOS=windows

set GOINSECURE=

set GOMODCACHE=c:\gopath\pkg\mod

set GONOPROXY=

set GONOSUMDB=

set GOOS=windows

set GOPATH=c:\gopath

set GOPRIVATE=

set GOPROXY=https://proxy.golang.org,direct

set GOROOT=C:\Program Files\Go

set GOSUMDB=sum.golang.org

set GOTMPDIR=

set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64

set GCCGO=gccgo

set AR=ar

set CC=gcc

set CXX=g++

set CGO_ENABLED=1

set GOMOD=C:\Users\user1\IdeaProjects\test\source\go.mod

set CGO_CFLAGS=-g -O2

set CGO_CPPFLAGS=

set CGO_CXXFLAGS=-g -O2

set CGO_FFLAGS=-g -O2

set CGO_LDFLAGS=-g -O2

set PKG_CONFIG=pkg-config

set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\user1\AppData\Local\Temp\go-build037891810=/tmp/go-build -gno-record-gcc-switches

What did you do?

Used time.sleep in a for ever loop generating data into a channel. Modfied the code below to be only 10000 generations. My rate was 5000 per second in go 1.15.8 but dropped to 200 in 1.16 and went back to 5000 when I reinstalled 1.15.8.

package main

import (
	"fmt"
	"time"
)

func main() {
mychan:= make(chan string, 5000)

go func(){

  for i:=0; i<10000;i++ {
    select {
      case foo:= <- mychan:
      fmt.Printf(foo)
    }
  }

}()


for {
   foo := "bar"
   time.Sleep(500 * time.Nanosecond)
   mychan<- foo
  }

}

What did you expect to see?

Higher rate of generation and submission into channel. Ticker also is affected as though time resolution is impacted in 1.16.
Channel queuing is not the problem. It is in the the Sleep function.

What did you see instead?

Lower rate. Time.Sleep and Ticker functionality appears impaired when tasked with high resolution function with durations in the Nanosecond or Microsecond range. This is NOT the case with 1.15.8 and below!

[tmthrgd]

This is a duplicate of #44343.

[seankhliao]

Duplicate of #44343