Comment 3 for bug 821610

I have written a testcase to check for this problem but interestingly even with full data journaling disabled I'm still seeing heavy performance impacts on Ubuntu 14.04 dev. In the attachments is the testcase. Just execute it with "chrt -i 0 ionice -c 3 ./test.py" and while it is running do a few minutes something else with your computer to see the difference.