Parallele_Verteilte_Systeme/EWD123/ewd123b/ewd123b.go

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/*
* ewd123b.go
*
* A program to represent the second mutex strategy, as described in EWD123.
*
* Copyright (c) 2019-2019 HS Emden/Leer
* All Rights Reserved.
*
* version 1.00 - 21 Oct 2019 - GJV - initial version
*
* author: Gert Veltink, gert.veltink@hs-emden-leer.de (GJV)
*/
package ewd123b
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import (
"../controller"
"log"
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"time"
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)
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// global synchronization variables
var c1, c2 = 1, 1
// Start starts the execution of EWD123b.
func Start() {
go process1()
go process2()
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/**
*/
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}
// process1 simulates the behaviour of the first process
func process1() {
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L1:
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//wait till c2 = 0 (other process no longer inside critical section)
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if c2 == 0 {
goto L1
}
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//if the other process inspects c1 at this moment both will enter the critical section
//we can force this behaviour if we wait for a moment
time.Sleep(100 * time.Millisecond)
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c1 = 0
controller.EnterCriticalSection(1)
controller.InsideCriticalSection(1, 50)
controller.LeaveCriticalSection(1)
c1 = 1
controller.OutsideCriticalSection(1, 100)
if controller.ProcessCrashed(0.1) {
log.Println("Process 1 crashed")
return
}
goto L1
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}
// process2 simulates the behaviour of the second process
func process2() {
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L2:
if c1 == 0 {
goto L2
}
c2 = 0
controller.EnterCriticalSection(2)
controller.InsideCriticalSection(2, 50)
controller.LeaveCriticalSection(2)
c2 = 1
controller.OutsideCriticalSection(2, 100)
if controller.ProcessCrashed(0.1) {
log.Println("Process 2 crashed")
return
}
goto L2
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}