Start irqbalance by default

Soren Hansen soren at
Fri Jan 15 13:38:44 GMT 2010

On Mon, Jan 11, 2010 at 11:23:43AM +0000, Matt Zimmerman wrote:
> I'm not sure why it needs to run all the time, though, rather than
> (say) as a cron job.  It has a --oneshot option which might be
> suitable for this.

FWIW, it automatically switches to oneshot mode on single-CPU,
multi-core systems, so it only sticks around on "actual" multi-CPU
systems. I think those are a rare breed among desktop systems.

>> Does userspace have more information about which processes are
>> running and what they are going to do? If so, doesn't that involve
>> more IPC and thus wakeups? If not, why isn't that alternative
>> strategy implemented in the kernel itself (right now it seems that
>> the scheduling would be done at two places?)
> It's looking at statistical behavior, e.g. how many IRQs particular
> devices have generated over a period of minutes or hours, and uses
> that information to provide the kernel with scheduling hints.  I think
> running it a few times per hour at most would be sufficient.

I don't think a rescheduling interval of more than a minute is really
very useful.

>> Chuck, did you actually intend to install this on all desktop systems
>> as well, or just servers (where performance might matter more).
> It seems appropriate for both.

I concur.

Soren Hansen                 | 
Lead virtualisation engineer | Ubuntu Server Team
Canonical Ltd.               |
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