Messages in this thread | | | Subject | Re: [PATCH 8/15] sched: Add parameter sched_mn_power_savings to control MN domain sched policy | From | Peter Zijlstra <> | Date | Mon, 24 Aug 2009 17:45:14 +0200 |
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On Mon, 2009-08-24 at 21:02 +0530, Vaidyanathan Srinivasan wrote: > * Peter Zijlstra <peterz@infradead.org> [2009-08-24 16:56:18]: > > > On Thu, 2009-08-20 at 15:39 +0200, Andreas Herrmann wrote: > > > Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> > > > --- > > > > > +#ifdef CONFIG_SCHED_MN > > > + if (!err && mc_capable()) > > > + err = sysfs_create_file(&cls->kset.kobj, > > > + &attr_sched_mn_power_savings.attr); > > > +#endif > > > > *sigh* another crappy sysfs file > > > > Guys, can't we come up with anything better than sched_*_power_saving=n? > > > > This configuration space is _way_ too large, and now it gets even > > crazier. > > Hi Peter and Andreas, > > Actually we had sched_power_savings and related simplifications, but > that did not really simplify the interface.
Well, I prefer a single sched_power knob that either goes on or off.
A user really isn't interested in exploring a 3^3 configuration space {PERF, POWER, POWER-WAKE-BALANCE} x {SMT, MC, MN} in order to find what works best.
> As for this mulit-node MN stuff, Gautham had posted a better solution > to propagate the sched_mc flags without need for new sysfs file and > related changes. > > Please take a look at: http://lkml.org/lkml/2009/3/31/137 and > http://lkml.org/lkml/2009/3/31/142 which actually degenerates the > domain.
Ah, right, that got lost in my inbox :/ Let me go read those too.
> However Andreas's requirement seem to indicate multiple nodes within > a single socket. I did not yet completely understand that topology. > Some for of smart degeneration may save an additional tunable here.
Yes, apparently AMD is going to put multiple nodes in a single socket, not sure how they do that, Andreas do these chips have multiple memory busses?
I was thinking chips were pin constrained and wouldn't add a whole second memory interface to the package, but what do I know...
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