[Pkg-xfce-devel] Bug#637631: Severe RAID0 performance drop after starting xfce4-power-manager

Björn A. Herwig baherwig at gmx.de
Sat Aug 13 08:58:26 UTC 2011

Package: xfce4-power-manager
Version: 1.0.10-4
Severity: important

Whenever xfce4-power-manager is started, the RAID0 performance drops severely:

$ sudo hdparm -t /dev/md0

 Timing buffered disk reads: 624 MB in  3.01 seconds = 207.47 MB/sec
$ xfce4-power-manager
$ sudo hdparm -t /dev/md0

 Timing buffered disk reads: 452 MB in  3.01 seconds = 150.33 MB/sec

Furthermore it seems that the rootfs gets remounted showing the following line 
in dmesg:

[   36.443770] EXT4-fs (sda1): re-mounted. Opts: 

The problem shows on two of my systems, both running an up-to-date Testing 
with EXT4 rootfs on SSD and /home with XFS on RAID0 (via device-mapper) HDDs.

The performance is only regained after reboot, stopping xfce4-power-manager 
has no effect.

Changing "spin-down-on-ac" 
in .config/xfce4/xfconf/xfce-perchannel-xml/xfce4-power-manager.xml has no 
effect, too.

The performance drop could be related to AAM, as I get the same drop when 
setting "hdparm -M128" for the RAID disks.

As an interim solution I removed xfce4-power-manager from autostart.


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