Re: [tip:sched/core] sched/isolation: Document the isolcpus= flags

[Mike Galbraith]

On Mon, 2017-10-30 at 17:11 +0100, Peter Zijlstra wrote:
> On Mon, Oct 30, 2017 at 10:48:04AM -0500, Christopher Lameter wrote:
> > On Fri, 27 Oct 2017, Peter Zijlstra wrote:
> > 
> > > I _strongly_ object to this statement, isolcpus is _not_ the preferred
> > > way, cpusets are.
> > >
> > > And yes, while cpusets suffers some problems, we _should_ really fix
> > > those and not promote this piece of shit isolcpus crap.
> > 
> > Well low level control at the processor level is important and this allows
> > controlling activities on a processor that is supposed to be dedicated to
> > certain activities without OS interaction.
> > 
> > isolcpus is the *right* approach here because you are micromanaging the OS
> > and are putting dedicated pieces of software on each core.
> 
> That is what you want, and cpusets should allow for that just fine.
> 
> > A cgroup suggests that threads would be scheduled over multiple cores
> > which is *not* what you want.
> 
> No, that suggestion is false. cpusets should allow you to isolate
> individual CPUs just fine.

It does. ÂI do RT jitter testing with it regularly. ÂIf it didn't work,
my 8 socket box would let me know instantly, by completely sucking :)

	-Mike