> -----Original Message----- > From: Song Bao Hua (Barry Song) > Sent: Wednesday, March 24, 2021 12:15 PM > To: 'Tim Chen' <tim.c.chen@xxxxxxxxxxxxxxx>; catalin.marinas@xxxxxxx; > will@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; vincent.guittot@xxxxxxxxxx; bp@xxxxxxxxx; > tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; lenb@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; > dietmar.eggemann@xxxxxxx; rostedt@xxxxxxxxxxx; bsegall@xxxxxxxxxx; > mgorman@xxxxxxx > Cc: msys.mizuma@xxxxxxxxx; valentin.schneider@xxxxxxx; > gregkh@xxxxxxxxxxxxxxxxxxx; Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>; > juri.lelli@xxxxxxxxxx; mark.rutland@xxxxxxx; sudeep.holla@xxxxxxx; > aubrey.li@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; x86@xxxxxxxxxx; > xuwei (O) <xuwei5@xxxxxxxxxx>; Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>; > guodong.xu@xxxxxxxxxx; yangyicong <yangyicong@xxxxxxxxxx>; Liguozhu (Kenneth) > <liguozhu@xxxxxxxxxxxxx>; linuxarm@xxxxxxxxxxxxx; hpa@xxxxxxxxx > Subject: RE: [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86 > > > > > -----Original Message----- > > From: Tim Chen [mailto:tim.c.chen@xxxxxxxxxxxxxxx] > > Sent: Wednesday, March 24, 2021 11:51 AM > > To: Song Bao Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx>; > > catalin.marinas@xxxxxxx; will@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; > > vincent.guittot@xxxxxxxxxx; bp@xxxxxxxxx; tglx@xxxxxxxxxxxxx; > > mingo@xxxxxxxxxx; lenb@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; > > dietmar.eggemann@xxxxxxx; rostedt@xxxxxxxxxxx; bsegall@xxxxxxxxxx; > > mgorman@xxxxxxx > > Cc: msys.mizuma@xxxxxxxxx; valentin.schneider@xxxxxxx; > > gregkh@xxxxxxxxxxxxxxxxxxx; Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>; > > juri.lelli@xxxxxxxxxx; mark.rutland@xxxxxxx; sudeep.holla@xxxxxxx; > > aubrey.li@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; x86@xxxxxxxxxx; > > xuwei (O) <xuwei5@xxxxxxxxxx>; Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>; > > guodong.xu@xxxxxxxxxx; yangyicong <yangyicong@xxxxxxxxxx>; Liguozhu > (Kenneth) > > <liguozhu@xxxxxxxxxxxxx>; linuxarm@xxxxxxxxxxxxx; hpa@xxxxxxxxx > > 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@xxxxxxxxxxxxxxx> > > > > > > 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@xxxxxxxxxxxxxxx> > > > Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx> > > > > > > Barry, > > > > Can you also add this chunk to the patch. > > Thanks. > > Sure, Tim, Thanks. I'll put that into patch 4/4 in v6. Hi Tim, You might want to take a look at this qemu patchset: https://lore.kernel.org/qemu-devel/20210331095343.12172-1-wangyanan55@xxxxxxxxxx/T/#t someone is trying to leverage this cluster topology to improve KVM virtual machines performance. > > > > > 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
