[PlanetCCRMA] CPU shielding by turning off the irqbalance systemd unit

[Fernando Lopez-Lezcano]

On 10/24/2013 11:02 PM, Tony White wrote:
> Hi all,
> I have a quick question please which someone may be able to answer for me.
> According to the rt wiki :
> https://rt.wiki.kernel.org/index.php/CPU_shielding_using_/proc_and_/dev/cpuset
> irqbalance should be disabled when using the realtime patch set.
> So my question is : Am I doing the right thing by disabling irqbalance
> when I run kernel-rt or is that information on the wiki out of date?

Hmmm, I really don't know.

> Just for those who are interested in doing the same also; I am using
> kdesu systemctl stop irqbalance to do this; (su -c 'systemctl stop
> irqbalance' for non kde systems, gksu systemctl stop irqbalance for
> gnome users.) As I remember it; I think that irqbalance is enabled by
> default on every Fedora install. So everyone could be running it unless
> they have explicitly turned it off.

Correct.

Is there a specific problem you are finding that needs this tweak? I run 
the rt patched kernel without doing that and I can get very good 
performance out of it. The only tuning I do is to (of course) make sure 
I run rtirq. Setting the cpu governor to "performance" also seems to 
help (although there are people that argue it is not necessary to do 
that, I find it helps get the best performance with the hardware I have 
tested with).

-- Fernando