kcryptd uses exorbient cpu during write

[Alex R]

I have my entire hard disk encrypted using dm-crypt (except a small boot partition). The encrypted partition is then used as a pv for LVM and then used for lvs.

alex@dell:~$ lsb_release -rd
Description: Ubuntu 9.04
Release: 9.04
alex@dell:~$ uname -a
Linux dell 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:58:03 UTC 2009 x86_64 GNU/Linux
alex@dell:~$ apt-cache policy linux-generic
linux-generic:
  Installed: 2.6.28.11.15
  Candidate: 2.6.28.11.15
  Version table:
 *** 2.6.28.11.15 0
        500 http://mirrors.acm.jhu.edu jaunty/restricted Packages
        100 /var/lib/dpkg/status

When performing a write of any size larger than about 50MB, top indicates that kcryptd is taking up more cpu than anything else. With writes upwards in size of 250MB, my cpu gets saturated. In combination with rsync, this results in my computer being only barely usable until rsync finishes.

This did _not_ happen until I upgraded from Intrepid to Jaunty.

[Alex R (rpglover64)]

This is probably also relevant: I was running 32 bit Intrepid.

[benbennett (benbennett)]

Same problem with my box , using raid 1 have 64-bit too , so it isn't an issue.
Description: Ubuntu 9.04
Release: 9.04

Linux xpslappy 2.6.28-14-generic #47-Ubuntu SMP Sat Jul 25 01:19:55 UTC 2009 x86_64 GNU/Linux

Cpu is at 50% usage while transfering 8GB , this also becomes an issue when running virtual machines.

[benbennett (benbennett)]

Duplicate of https://bugs.launchpad.net/ubuntu/+source/linux/+bug/386716