[RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86

[Song Bao Hua (Barry Song)]

> -----Original Message-----
> From: Tim Chen [mailto:tim.c.chen at linux.intel.com]
> Sent: Wednesday, March 24, 2021 11:51 AM
> To: Song Bao Hua (Barry Song) <song.bao.hua at hisilicon.com>;
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> Subject: Re: [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86
> 
> 
> 
> On 3/18/21 9:16 PM, Barry Song wrote:
> > From: Tim Chen <tim.c.chen at linux.intel.com>
> >
> > There are x86 CPU architectures (e.g. Jacobsville) where L2 cahce
> > is shared among a cluster of cores instead of being exclusive
> > to one single core.
> >
> > To prevent oversubscription of L2 cache, load should be
> > balanced between such L2 clusters, especially for tasks with
> > no shared data.
> >
> > Also with cluster scheduling policy where tasks are woken up
> > in the same L2 cluster, we will benefit from keeping tasks
> > related to each other and likely sharing data in the same L2
> > cluster.
> >
> > Add CPU masks of CPUs sharing the L2 cache so we can build such
> > L2 cluster scheduler domain.
> >
> > Signed-off-by: Tim Chen <tim.c.chen at linux.intel.com>
> > Signed-off-by: Barry Song <song.bao.hua at hisilicon.com>
> 
> 
> Barry,
> 
> Can you also add this chunk to the patch.
> Thanks.

Sure, Tim, Thanks. I'll put that into patch 4/4 in v6.

> 
> Tim
> 
> 
> diff --git a/arch/x86/include/asm/topology.h
> b/arch/x86/include/asm/topology.h
> index 2a11ccc14fb1..800fa48c9fcd 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -115,6 +115,7 @@ extern unsigned int __max_die_per_package;
> 
>  #ifdef CONFIG_SMP
>  #define topology_die_cpumask(cpu)		(per_cpu(cpu_die_map, cpu))
> +#define topology_cluster_cpumask(cpu)		(cpu_clustergroup_mask(cpu))
>  #define topology_core_cpumask(cpu)		(per_cpu(cpu_core_map, cpu))
>  #define topology_sibling_cpumask(cpu)		(per_cpu(cpu_sibling_map, cpu))
> 

Thanks
Barry