> -----Original Message----- > From: Song Bao Hua (Barry Song) > Sent: Wednesday, March 24, 2021 12:15 PM > To: 'Tim Chen' <[email protected]>; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; > [email protected]; [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected] > Cc: [email protected]; [email protected]; > [email protected]; Jonathan Cameron <[email protected]>; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > xuwei (O) <[email protected]>; Zengtao (B) <[email protected]>; > [email protected]; yangyicong <[email protected]>; Liguozhu (Kenneth) > <[email protected]>; [email protected]; [email protected] > Subject: RE: [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86 > > > > > -----Original Message----- > > From: Tim Chen [mailto:[email protected]] > > Sent: Wednesday, March 24, 2021 11:51 AM > > To: Song Bao Hua (Barry Song) <[email protected]>; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected] > > Cc: [email protected]; [email protected]; > > [email protected]; Jonathan Cameron <[email protected]>; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > xuwei (O) <[email protected]>; Zengtao (B) <[email protected]>; > > [email protected]; yangyicong <[email protected]>; Liguozhu > (Kenneth) > > <[email protected]>; [email protected]; [email protected] > > 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 <[email protected]> > > > > > > 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 <[email protected]> > > > Signed-off-by: Barry Song <[email protected]> > > > > > > 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/[email protected]/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
