PyQt: How to Know Progress of a Process Running background

Question

Hello there. Im in real confusion with the ProgressBar mechanisms. However now i need help on this "Can we know the percentage completion or time remaining of completion of a Process, that has been initiated from a Qt interface like this `

    self.process = QProcess()
    self.connect(self.process, SIGNAL("readyReadStdout()"), self.readOutput)
    self.connect(self.process, SIGNAL("readyReadStderr()"), self.readErrors)  
    tarsourcepath="sudo tar xvpf "+ self.path1  
    self.process.setArguments(QStringList.split(" ",tarsourcepath))
    self.textLabel3.setText(self.__tr("Extracting....."))                
    self.process.start()`

slots readOUtput just implements the collection of data fron stdout and transferring it to a text browser. I need to know is there any way we could monitor the ongoing process, making to knowpercentage completion, so that i can manage a progressbar for this.

Thanks Experts