It appears to be the kernel bug. Sort of. I've bisected the kernel to commit ab8fabd46f811d5153d8a0cd2fac9a0d41fb593d. There's a discussion of this problem in this thread: https://groups.google.com/forum/#!topic/linux.kernel/Jc69VRli3k0
This seems basically WONTFIX from linux side. But a workarounds are: 1. "vm.highmem_is_dirtyable=1" sysctl option — although this makes the performance not as high as it was in 3.2.x kernels, it at least allows one to use the disk subsystem 2. "mem=15G" kernel parameter limits the amount of usable memory, preventing the problems discussed in the thread I linked above 3. Use 64 bit kernel. This seems to be not a trivial thing to do with Ubuntu, but I may be wrong. But this is proposed as _the solution_. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1342341 Title: upowerd kills USB performance To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/upower/+bug/1342341/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
