Re: 2.6.12-rc2-mm1

Siddha, Suresh B
2005-04-05T18:56:46Z

On Tue, Apr 05, 2005 at 05:33:49PM +1000, Nick Piggin wrote:
> Andrew Morton wrote:
>
> > +sched-remove-unnecessary-sched-domains.patch
> > +sched-improve-pinned-task-handling-again.patch
> [snip]
> >
> > CPU scheduler updates
> >
>
> It is no problem that you picked these up for testing. But
> don't merge them yet, please.
>
> Suresh's underlying problem with the unnecessary sched domains
> is a failing of sched-balance-exec and sched-balance-fork, which

That wasn't the only motivation. For example, on non-HT cpu's we shouldn't
be setting up SMT sched-domain, same with NUMA domains on non-NUMA systems.

> I am working on now.
>
> Removing unnecessary domains is a nice optimisation, but just
> needs to account for a few more flags before declaring that a

Can you elaborate when we require a domain with special flags but has
no or only one group in it.

> domain is unnecessary (not to mention this probably breaks if
> isolcpus= is used). I have made some modifications to the patch

I have tested my patch with "ioslcpus=" and it works just fine.

> to fix these problems.
>
> Lastly, I'd like to be a bit less intrusive with pinned task
> handling improvements. I think we can do this while still being
> effective in preventing livelocks.

We want to see this fixed. Please post your patch and I can let you know
the test results.

>
> I will keep you posted with regards to the various scheduler
> patches.

Nick, Can you post the patches you sent me earlier to this list?

thanks,
suresh