On Apr 27, 2012, at 9:53 AM, Jeff Moyer wrote:
Chris Murphy <lists(a)colorremedies.com> writes:
> 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:
> 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
Sounds like lazy itable init. Try mkfs -t ext4 -E lazy_itable_init=0.
This is happening on internal disks, targeted for Fedora installation. I can hear it once
install is complete, still booted from DVD media. Is this a bug?