Ubuntu
linux package

  1. Bug #1264707
  2. Comment #24

Comment 24 for bug 1264707

Revision history for this message
Ilya Murav'jov (muravjov-il) wrote : Re: IO limit 1.2 MB/s for 32bit ubuntu (ACPI issues)

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).