Normally top reports CPU line, sy at 0.4% when idle. If I format an external Firewire disk as btrfs and mount it, it remains at 0.4%. If I reformat as XFS and mount it, again top reports sy at 0.4%. However, if I reformat as ext4 and mount it, sy runs at 3.5%. These two processes are now at the top of top's results: kworker/1:2 kworker/0:4 Each uses on average 1.9% CPU. The light on the external drive flashes 4x per second. There are no processes using the disk at all while this is going on. If I umount it, the pulsing stops. If I remount it, the pulsing resumes as does the slightly higher CPU consumption. This doesn't happen with the same hardware mounted XFS or btrfs or HFS+. Odd? These reveal nothing related to the disk: lsof | grep sdb lsof | mapper If I sift through it unfiltered with the volume mounted and not, I don't really see anything obvious standing out. Chris Murphy -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel