Comment 5 for bug 900923

Steve, I've re-instrumented the journal-commit tests this time using the following test methodology:

Start banshee playing some classical music (mp3)
Sleep 60 seconds
Start firefox, open tab on a blog containing flash adverts
Sleep 60 seconds
Open 2nd tab on firefox on a blog with lots of images, flash videos and adverts
Sleep 60 seconds
Open 3rd tab on firefox on slashdot.com
Sleep 60
Open 4th tab on firefox on boingboing.com
Sleep 60
Start thunderbird on an IMAP gmail mailbox (note, the folders
were pre-sync'd before running the test)
Sleep 60
kill banshee
Sleep 60
kill firefox
Sleep 60
Kill thunderbird
Sleep 20

This was run 5 x for two scenarios: journal-commit not enabled and journal commit enabled. I calculated the average and standard deviation. I ran this test methodology on two machines, a 64 bit Lenovo ThinkPad x220i (HDD) and a 32 bit HP mini 100 (SSD).

Attached is a LibreOffice spreadsheet of the data.

In both sets of tests there is no positive power saving, in fact the differences are within the the error margin of the measurements, so I can't see any positive benefit.

I could re-run these tests over night on the x220i with different values for the journal commit time if you want more data, but I really suspect we won't anything much different.