Hi,<div>here is my problem</div><div>1 ./configure --enable-trace-backends=simple</div><div>&nbsp; &nbsp; make</div><div>&nbsp; &nbsp; make install</div><div>&nbsp; &nbsp; echo virtio_notity &gt; /tmp/events</div><div>&nbsp; &nbsp; echo virtio_queue_notify &gt;&gt; /tmp/events</div><div>2 &nbsp;I use a xml file run a virtual machine</div><div>3 &nbsp;qemu-system_x86_64 -trace events=/tmp/events&nbsp;</div><div>4 &nbsp;&nbsp;./scripts/simpletrace.py trace-events trace-*</div><div><br></div><div>But do not get trace.log. and when i check trace-* using 'vim' i find the file is almost empty.</div><div>I tried many times, including reinstall qemu,but still don't work.</div><div>when i use qemu -trace -m 2048 ........... commandline create virtual machine ,the vm become very slow and still no trace.log.</div><div>I am a green hand, help!!!!! &nbsp;&nbsp;</div>