After investigating UPower sources I've triaged the problem to this: "/usr/sbin/pm-powersave false" => "/usr/lib/pm-utils/power.d/laptop-mode false" => "echo 10 > /proc/sys/vm/dirty_ratio"
If I change /proc/sys/vm/dirty_ratio to any different value (more or less than previous value!) then I got my issue. That is, at startup I have dirty_ratio equal to 20 and I should leave it unchanged (neither 19 nor 21 may be used) if I don't want to get 1Mb/s speed. :) I've read a few articles about dirty_ratio' impact to IO; nevertheless I believe it is a bug. Any ideas? Also I'll try another scenario tonight: I have 32Gb RAM now so I try to increase swap size from 8Gb to 32Gb, and then run "sysctl -w vm.swappiness=100" (maybe it helps to offload IO activity). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1264707 Title: IO limit 1.2 MB/s for 32bit ubuntu (ACPI issues) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1264707/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
