kcryptd process doesn't utilize multiple cpus
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Debian |
New
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Incomplete
|
Undecided
|
Unassigned |
Bug Description
Hardware:
2xIntel Xeon Quad Core @2.2ghz
Ubuntu 8.04.1 AMD64
8GB FB-DIMM ram
2xSAS 15000RPM in Hardware Raid as operating system
7xSamsung 1TB SATA in Software Raid (/dev/md0) entire volume put in lvm and encrypted to (/dev/mycrypt)
/dev/md0 has a sustained read/write of 300-400MB/s whereas /dev/mycrypt has a mere 70-90MB/s.
I believe the bottleneck lies in the lack of parallelism in the kcryptd process. This process tops out at %100 cpu usage and will not utilize more cpus.
Running multiple read/write processes (tested using dd) does not increase throughput.
Is there a configuration somewhere to allow kcryptd to multithread, or does the current code lack this functionality? If this functionality is not already implemented then is there a reason such as security or synchronization?
Changed in linux (Ubuntu): | |
status: | New → Confirmed |
The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:
1) If you are comfortable installing packages on your own, the linux-image- 2.6.27- * package is currently available for you to install and test.
--or--
2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http:// www.ubuntu. com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.
Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.