[Bug 653611] Re: extremely bad dm-crypt latency
** Changed in: linux (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
Seems like I should have been testing 2.6.38-rc2 better. I checked a few days ago, benchmarked and tought I had forgotten to revert the patch. Went back to 2.6.37, because standby on my machine is broken with in 2.6.38. Just compiled a pristine mainline 2.6.38-rc2 to be sure and it really seems fixed (4500 seeks/second -> 3700), the same values I get with the patched 2.6.37 or 2.6.32. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
Thanks Michael. I knew the mentioned posts. I just tried the current Natty kernel 2.6.38-020638rc2-generic. Looks like it's solved there. Seeker v2.0, 2007-01-15, http://www.linuxinsight.com/how_fast_is_your_disk.html Benchmarking /dev/sda [152627MB], wait 30 seconds.. Results: 4543 seeks/second, 0.22 ms random access time -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
There is a bit progress, you can read the details at http://www.linux- archive.org/device-mapper-development/474248-problem-ssd-access-time-dm- crypt-way-too-high.html. There are currently two patches, which completely resolve the issue for me, but have their own problems and presumably won't go into mainline. There is also a bugreport about similar issues on the kernel bugzilla (https://bugzilla.kernel.org/show_bug.cgi?id=17892), but since the issues persist with 2.6.32, it could be another problem. ** Bug watch added: Linux Kernel Bug Tracker #17892 http://bugzilla.kernel.org/show_bug.cgi?id=17892 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
I can confirm it too for 2.6.35-24-generic. Is there any progress? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
I can confirm this with 2.6.32-27-generic (find / 10.5 s) and 2.6.33-02063301-generic (176.3 s). ** Attachment added: "ssd_find.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1794497/+files/ssd_find.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/653611 Title: extremely bad dm-crypt latency -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
Note that listing all files with find (exact commandline see below) is 34 times faster on 2.6.32 (367s vs 10.7s). # echo 1 > /proc/sys/vm/drop_caches # time find / > /dev/null ** Attachment added: "LatencyTOP information about find, while listing all files on the root partition with 2.6.32 (10.7 seconds)" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666560/+files/latencytop-find-2.6.32.png ** Tags added: dm-crypt kernel-bug latency regression-release -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
** Attachment added: "LatencyTOP information about find, while listing all files on the root partition with 2.6.35 (367 seconds)" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666559/+files/latencytop-find-2.6.35.png -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
Note the huge difference in the amount of context-switches. ** Attachment added: "vmstat output during the palimpsest benchmark under 2.6.32" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666558/+files/vmstat-palimpsest-2.6.32.txt -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
Ignore the performance spikes, these are caused by empty space, which the firmware of the drive handles faster. Comparing the encrypted disk (2.6.32) with the raw disk, there seems to be virtually no performance penalty. ** Attachment added: "Raw disk benchmarked under 2.6.32, 0.2ms latency" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666556/+files/palimpsest-unencrypted.png -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
** Attachment added: "vmstat output during the palimpsest benchmark under 2.6.35" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666557/+files/vmstat-palimpsest-2.6.35.txt -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
** Attachment added: "Encrypted disk benchmarked under 2.6.32, 0.2ms latency" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/653611/+attachment/1666554/+files/latencytop-find-2.6.32.png -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 653611] Re: extremely bad dm-crypt latency
** Attachment added: "Encrypted disk benchmarked under 2.6.35, 10.1ms latency" https://bugs.launchpad.net/bugs/653611/+attachment/1666553/+files/palimpsest-2.6.35.png -- extremely bad dm-crypt latency https://bugs.launchpad.net/bugs/653611 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
