Lessons not Learned - Continuing Latency Issues in Linux

We still have wonderful fsync offenders. Look at Kopete for example, or at Chrome. You don't want to be running that on battery or in a low latency environment:

Process kopete (1868)            Total: 19098.1 msec

fsync() on a file        6008.6 msec    99.8 %

Scheduler: waiting for cpu   19.4 msec  0.2 %

Or Iron (a privacy-enhanced Chrome/Chromium browser)

Process iron (5822)  Total: 13753.6 msec
fsync() on a file           5090.9 msec   70.3 %
Writing a page to disk 1412.8 msec 10.3 %
synchronous write         524.5 msec  3.8 %

If you use ext4, you can add some of these mount options to decrease the latency impact. But this decreases data security:
noatime,nodiratime,nobh,barrier=0,commit=100,data=writeback