Re: 2.6.4-mm1

[Andrew Morton]

Andi Kleen <ak@xxxxxx> wrote:
>
> Andrew Morton <akpm@xxxxxxxx> writes:
> 
> > - The CPU scheduler changes in -mm (sched-domains) have been hanging about
> >   for too long.  I had been hoping that the people who care about SMT and
> >   NUMA performance would have some results by now but all seems to be silent.
> >
> >   I do not wish to merge these up until the big-iron guys can say that they
> >   suit their requirements, with a reasonable expectation that we will not
> >   need to churn this code later in the 2.6 series.
> >
> >   So.  If you have been testing, please speak up.  If you have not been
> >   testing, please do so.
> 
> I tested them on Opteron NUMA systems and they are worse on simple
> tests than the stock scheduler (e.g. the parallelized STREAM test,
> which is a bit silly, but still fairly important)

OK, thanks.

> For SMT there is a patch from Intel pending that teaches x86-64
> to set up the SMT scheduler. They said they got slightly better
> benchmark results. The SMT setup seems to be racy though.

Am I correct in thinking that this patch provides the necessary hooks to
integrate x86_4 into the new functionality which sched-domains provides, or
is the Intel patch independent of sched-domains?

> Some kind of SMT scheduler is definitely needed, we have a serious
> regression compared to 2.4 here right now. I'm not sure this 
> is the right approach though, it seems to be far too complex.

Well that's discouraging.  I really do want to push this thing along a bit.

Yours is the only report of regression of which I am aware.  Is the reason
understood?

And is anyone developing alternative SMT enhancements?
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