Comment 150 for bug 131094

I have been looking at this and running informal (read sloppy) tests today.

For the people upgrading from older systems perhaps the problem is with relatime in the fstab being missing.

I was testing by running "vi 123" while "dd if=/dev/zero of=~/test2 bs=2M count=2048&"

I tried all 4 schedulers and all took a long while (30 secs+) to an active vi screen.

Now it is below 10.

I tried different schedulers and they were all slow. Now CFQ (default?) is what I am using (have not compared if less than 10 seconds will drop to less than 5).

The system-cleaner (Applications --> System Tools --> System Cleaner) identified the lack of relatime for me.

It could also simply be rebooting that caused the speed up too though.

It is only speculation that the upgrade missed that, but I may have removed it myself by accident at some point.

To change schedulers without rebooting:

as root (run "sudo bash", or someone correct how to redirect while using sudo)

echo "scheduler name" > /sys/block/sdx/queue/scheduler (where x is the drive e.g. /sda).

for a list of schedulers and what is selected run cat on the same file

example:
$cat /sys/block/sda/queue/scheduler
noop anticipatory deadline [cfq]

I am not at my desktop, so I can't confirm weather this is simply for command line and I will see similar problems to Jamie above.

In a few days I can follow-up if long uptime (for a desktop) is the problem.