Comment 10 for bug 578930

Revision history for this message
Serge Hallyn (serge-hallyn) wrote : Re: Lucid qemu-kvm: ksmd default config is CPU hog

Thanks for the info Nullzone! Based on your data, I'm going to spend a
bit of time running with:

# To disable qemu-kvm's page merging feature, set KSM_ENABLED=0 and
# sudo restart qemu-kvm

 KSM_ENABLED=1
 #SLEEP_MILLISECS=2000
 SLEEP_MILLISECS=50
 PAGES_TO_SCAN=100

in my /etc/default/qemu-kvm, and

  if [ -w /sys/kernel/mm/ksm/pages_to_scan ]; then
   if [ -n "$PAGES_TO_SCAN" ]; then
    echo "$PAGES_TO_SCAN" > /sys/kernel/mm/ksm/pages_to_scan
   fi
  fi

added to my /etc/init/qemu-kvm.conf

I think upping sleep_millisec for Natty is a good idea. But not
for Lucid+Maverick, it's just too late, and after all these are
trivially changeable and really ought to be customized anyway.

I also think (obviously) that adding KSM_PAGES_TO_SCAN to the list of
variables which /etc/init/qemu-kvm can read seems worthwhile. However
again I'm not sure whether I want to ask for a feature freeze exception
for maverick for this. I personally think it's better to wait for Natty.
Thierry, do you concur, or should I try for maverick?