Seems to be fixed in 13.10 daily (Sun 18 Aug 2013 20:58:40 EDT) I get about 5.6 GB/s on both cache of both encrypted and normal disks
Fresh install in VertualBox. sudo -i cryptsetup -c aes-xts-plain -s 512 luksFormat /dev/sdb cryptsetup luksOpen /dev/sdb crypttest mkfs.ext4 /dev/mapper/crypttest mkdir /media/crypt mount /dev/mapper/crypttest /media/crypt dd if=/dev/urandom of=/media/crypt/test.dat bs=1M count=1024 cp /media/crypt/test.dat ~/test.dat dd if=~/test.dat of=/dev/null bs=1M count=1024 dd if=~/test.dat of=/dev/null bs=1M count=1024 dd if=/media/crypt/test.dat of=/dev/null bs=1M count=1024 dd if=/media/crypt/test.dat of=/dev/null bs=1M count=1024 ** Changed in: linux (Ubuntu) Status: Incomplete => Fix Released -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/875733 Title: disk cache is slow on average with dm-crypt Status in “linux” package in Ubuntu: Fix Released Bug description: I would expect the cached read speeds to be the same as the cache is above the encryption device mapper layer. Using dm-crypt read speeds are inconsistent averaging 380 MB/s, not using dm-crypt read speeds are consistently 1200 MB/s. I used dd to test at least 12 times: dd if=./test.file of=/dev/null bs=1M count=1024 lsb_release -rd: Description: Ubuntu 10.04.3 LTS Release: 10.04 apt-cache policy cryptsetup: cryptsetup: Installed: 2:1.1.0~rc2-1ubuntu13 Candidate: 2:1.1.0~rc2-1ubuntu13 Version table: *** 2:1.1.0~rc2-1ubuntu13 0 500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages 100 /var/lib/dpkg/status --- AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21. AplayDevices: Error: [Errno 2] No such file or directory Architecture: i386 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/controlC0', '/dev/snd/hwC0D2', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/timer'] failed with exit code 1: CRDA: Error: [Errno 2] No such file or directory Card0.Amixer.info: Error: [Errno 2] No such file or directory Card0.Amixer.values: Error: [Errno 2] No such file or directory DistroRelease: Ubuntu 10.04 HibernationDevice: RESUME=UUID=bedd48c0-3471-4c24-931d-ce224b3f746c MachineType: Dell Inc. Dell DV051 Package: linux (not installed) ProcCmdLine: root=UUID=bae54c1d-5f65-4a70-bff5-e9200e4ab461 ro quiet splash ProcEnviron: LANG=en_US.UTF-8 SHELL=/bin/bash ProcVersionSignature: Ubuntu 2.6.32-33.72-generic-pae 2.6.32.41+drm33.18 Regression: No RelatedPackageVersions: linux-firmware 1.34.7 Reproducible: Yes RfKill: Tags: lucid filesystem needs-upstream-testing Uname: Linux 2.6.32-33-generic-pae i686 UserGroups: WifiSyslog: dmi.bios.date: 10/08/2005 dmi.bios.vendor: Dell Inc. dmi.bios.version: A03 dmi.board.name: 0JC474 dmi.board.vendor: Dell Inc. dmi.chassis.type: 6 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA03:bd10/08/2005:svnDellInc.:pnDellDV051:pvr:rvnDellInc.:rn0JC474:rvr:cvnDellInc.:ct6:cvr: dmi.product.name: Dell DV051 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/875733/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp