Re: How to disable group scheduler correctly?

From: Bill Davidsen
Date: Mon Jul 28 2008 - 13:20:32 EST


Paul Menage wrote:
On Sun, Jul 27, 2008 at 4:24 PM, Bill Davidsen <davidsen@xxxxxxx> wrote:
Would be nice to have a clean way to do this at runtime, so you could run a
distribution kernel and just avoid the group part of the scheduling.

If the cgroups scheduler is enabled but you don't actually create any
cpu scheduler cgroups, then you're just scheduling across a single
group that contains all processes/threads. Is that distinguishable
from not having group scheduling at all?

In decisions, hopefully not. But given that there are other places in kernel which allow code to be bypassed completely, a flag which would simply avoid ever going into the code would not be a new idea. In the network code there are flags to prevent passing packets in a bridge through iptables, something similar could be provided in scheduling. It actually makes sense to default the flag to "no cgroups" asnd only enable it if cgroups have been defined.

There is no optimization faster than not executing the code.

--
Bill Davidsen <davidsen@xxxxxxx>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/