问如何提高PyQt4 QListWidget的效率

EN

import sys
from math import *
#from PyQt4 import QtCore, QtGui
from PyQt4.QtCore import (Qt, SIGNAL, QSize)
from PyQt4.QtGui import (QApplication, QDialog, QLabel, QListWidget, QListWidgetItem,     QPushButton, QScrollArea, QTextDocument, QVBoxLayout)
from time import localtime, strftime
import time

class LogDlg(QDialog):

  def __init__(self, parent=None):
    super(LogDlg, self).__init__(parent)
    self.resize(450, 380)

    self.log1 = QListWidget()
    self.log2 = QListWidget()
    lbl = QLabel()
    lbl_2 = QLabel()
    lbl.setText("Communications Log")
    lbl_2.setText("Command/Data Log")
    self.pushButton = QPushButton()
    self.pushButton.setMaximumSize(QSize(110, 24))
    self.pushButton.setObjectName("pushButton")

    self.pushbutton = QPushButton
    self.pushButton.setText("Start Log Loop")
    layout = QVBoxLayout()
    layout.addWidget(self.pushButton)
    layout.addWidget(lbl)
    layout.addWidget(self.log1)
    layout.addWidget(lbl_2)
    layout.addWidget(self.log2)
    self.setLayout(layout)
    self.setWindowTitle("Transaction Logs")
    self.connect(self.pushButton,SIGNAL("clicked()"),self.logLoop) 
    self.time = time.time()

  def logLoop(self):
    for i in range(1000):
        print i
        self.addLog("This is a test","c",True)      

  def timeStamp(self):
    now = time.time()
    localtime = time.localtime(now)
    milliseconds = '%02d' % int((now - int(now)) * 100)
    val = time.strftime('%H:%M:%S.', localtime) + milliseconds
    return val

  def clearUi(self):
    self.log1.clear()
    self.log2.clear()

  def addLog(self, data, type="c", ts=False):
#        pass
    t = self.timeStamp()
    if ts == True:
        data = t + " " + data
    if type == "c":
        self.listItem1 = QListWidgetItem()
        self.listItem1.setText(data)
        self.log1.addItem(self.listItem1)
#        self.log1.scrollToItem(self.listItem1)
        self.log1.setCurrentItem(self.listItem1)


    elif type == "d":
        self.listItem2 = QListWidgetItem()
        self.listItem2.setText(data)
        self.log2.addItem(self.listItem2)
#        self.log2.scrollToItem(self.listItem2)
        self.log2.setCurrentItem(self.listItem2)


app = QApplication(sys.argv)
form = LogDlg()
form.open()
app.exec_()