Re: [RFC] sched: CPU topology try

From: Preeti U Murthy
Date: Tue Jan 07 2014 - 05:43:16 EST

On 01/07/2014 03:20 PM, Peter Zijlstra wrote:
> On Tue, Jan 07, 2014 at 03:10:21PM +0530, Preeti U Murthy wrote:
>> What if we want to add arch specific flags to the NUMA domain? Currently
>> with Peter's patch: and this patch,
>> the arch can modify the sd flags of the topology levels till just before
>> the NUMA domain. In sd_init_numa(), the flags for the NUMA domain get
>> initialized. We need to perhaps call into arch here to probe for
>> additional flags?
> What are you thinking of? I was hoping all NUMA details were captured in
> the distance table.
> Its far easier to talk of specifics in this case.
If the processor can be core gated, then there is very little power
savings that we could yield from consolidating all the load onto a
single node in a NUMA domain. 6 cores on one node or 3 cores each on two
nodes, the power is drawn by 6 cores in all. So I was thinking under
this circumstance we might want to set the SD_SHARE_POWERDOMAIN flag at
the NUMA domain and spread the load if it favours the workload.

Preeti U Murthy

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