diff mbox series

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

Message ID 20210319041618.14316-5-song.bao.hua@hisilicon.com (mailing list archive)
State New, archived
Headers show
Series scheduler: expose the topology of clusters and add cluster scheduler | expand

Commit Message

Song Bao Hua (Barry Song) March 19, 2021, 4:16 a.m. UTC
From: Tim Chen <tim.c.chen@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@linux.intel.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
---
 arch/x86/Kconfig                |  8 ++++++++
 arch/x86/include/asm/smp.h      |  7 +++++++
 arch/x86/include/asm/topology.h |  1 +
 arch/x86/kernel/cpu/cacheinfo.c |  1 +
 arch/x86/kernel/cpu/common.c    |  3 +++
 arch/x86/kernel/smpboot.c       | 43 ++++++++++++++++++++++++++++++++++++++++-
 6 files changed, 62 insertions(+), 1 deletion(-)

Comments

Tim Chen March 23, 2021, 10:50 p.m. UTC | #1
On 3/18/21 9:16 PM, Barry Song wrote:
> From: Tim Chen <tim.c.chen@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@linux.intel.com>
> Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>


Barry,

Can you also add this chunk to the patch.
Thanks.

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))
Song Bao Hua (Barry Song) March 23, 2021, 11:21 p.m. UTC | #2
> -----Original Message-----
> From: Tim Chen [mailto:tim.c.chen@linux.intel.com]
> Sent: Wednesday, March 24, 2021 11:51 AM
> To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>;
> catalin.marinas@arm.com; will@kernel.org; rjw@rjwysocki.net;
> vincent.guittot@linaro.org; bp@alien8.de; tglx@linutronix.de;
> mingo@redhat.com; lenb@kernel.org; peterz@infradead.org;
> dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com;
> mgorman@suse.de
> Cc: msys.mizuma@gmail.com; valentin.schneider@arm.com;
> gregkh@linuxfoundation.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> juri.lelli@redhat.com; mark.rutland@arm.com; sudeep.holla@arm.com;
> aubrey.li@linux.intel.com; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; linux-acpi@vger.kernel.org; x86@kernel.org;
> xuwei (O) <xuwei5@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> guodong.xu@linaro.org; yangyicong <yangyicong@huawei.com>; Liguozhu (Kenneth)
> <liguozhu@hisilicon.com>; linuxarm@openeuler.org; hpa@zytor.com
> 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@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@linux.intel.com>
> > Signed-off-by: Barry Song <song.bao.hua@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
Song Bao Hua (Barry Song) March 31, 2021, 10:07 a.m. UTC | #3
> -----Original Message-----
> From: Song Bao Hua (Barry Song)
> Sent: Wednesday, March 24, 2021 12:15 PM
> To: 'Tim Chen' <tim.c.chen@linux.intel.com>; catalin.marinas@arm.com;
> will@kernel.org; rjw@rjwysocki.net; vincent.guittot@linaro.org; bp@alien8.de;
> tglx@linutronix.de; mingo@redhat.com; lenb@kernel.org; peterz@infradead.org;
> dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com;
> mgorman@suse.de
> Cc: msys.mizuma@gmail.com; valentin.schneider@arm.com;
> gregkh@linuxfoundation.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> juri.lelli@redhat.com; mark.rutland@arm.com; sudeep.holla@arm.com;
> aubrey.li@linux.intel.com; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; linux-acpi@vger.kernel.org; x86@kernel.org;
> xuwei (O) <xuwei5@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> guodong.xu@linaro.org; yangyicong <yangyicong@huawei.com>; Liguozhu (Kenneth)
> <liguozhu@hisilicon.com>; linuxarm@openeuler.org; hpa@zytor.com
> Subject: RE: [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86
> 
> 
> 
> > -----Original Message-----
> > From: Tim Chen [mailto:tim.c.chen@linux.intel.com]
> > Sent: Wednesday, March 24, 2021 11:51 AM
> > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>;
> > catalin.marinas@arm.com; will@kernel.org; rjw@rjwysocki.net;
> > vincent.guittot@linaro.org; bp@alien8.de; tglx@linutronix.de;
> > mingo@redhat.com; lenb@kernel.org; peterz@infradead.org;
> > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com;
> > mgorman@suse.de
> > Cc: msys.mizuma@gmail.com; valentin.schneider@arm.com;
> > gregkh@linuxfoundation.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> > juri.lelli@redhat.com; mark.rutland@arm.com; sudeep.holla@arm.com;
> > aubrey.li@linux.intel.com; linux-arm-kernel@lists.infradead.org;
> > linux-kernel@vger.kernel.org; linux-acpi@vger.kernel.org; x86@kernel.org;
> > xuwei (O) <xuwei5@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> > guodong.xu@linaro.org; yangyicong <yangyicong@huawei.com>; Liguozhu
> (Kenneth)
> > <liguozhu@hisilicon.com>; linuxarm@openeuler.org; hpa@zytor.com
> > 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@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@linux.intel.com>
> > > Signed-off-by: Barry Song <song.bao.hua@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.

Hi Tim,
You might want to take a look at this qemu patchset:
https://lore.kernel.org/qemu-devel/20210331095343.12172-1-wangyanan55@huawei.com/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
Tim Chen April 20, 2021, 6:31 p.m. UTC | #4
On 3/23/21 4:21 PM, Song Bao Hua (Barry Song) wrote:

>>
>> On 3/18/21 9:16 PM, Barry Song wrote:
>>> From: Tim Chen <tim.c.chen@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@linux.intel.com>
>>> Signed-off-by: Barry Song <song.bao.hua@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.
> 

Barry,

This chunk will also need to be added to return cluster id for x86.
Please add it in your next rev.

Thanks.

Tim

---

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 800fa48c9fcd..2548d824f103 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -109,6 +109,7 @@ extern const struct cpumask *cpu_clustergroup_mask(int cpu);
 #define topology_physical_package_id(cpu)	(cpu_data(cpu).phys_proc_id)
 #define topology_logical_die_id(cpu)		(cpu_data(cpu).logical_die_id)
 #define topology_die_id(cpu)			(cpu_data(cpu).cpu_die_id)
+#define topology_cluster_id(cpu)		(per_cpu(cpu_l2c_id, cpu))
 #define topology_core_id(cpu)			(cpu_data(cpu).cpu_core_id)
 
 extern unsigned int __max_die_per_package;
Song Bao Hua (Barry Song) April 20, 2021, 10:31 p.m. UTC | #5
> -----Original Message-----
> From: Tim Chen [mailto:tim.c.chen@linux.intel.com]
> Sent: Wednesday, April 21, 2021 6:32 AM
> To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>;
> catalin.marinas@arm.com; will@kernel.org; rjw@rjwysocki.net;
> vincent.guittot@linaro.org; bp@alien8.de; tglx@linutronix.de;
> mingo@redhat.com; lenb@kernel.org; peterz@infradead.org;
> dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com;
> mgorman@suse.de
> Cc: msys.mizuma@gmail.com; valentin.schneider@arm.com;
> gregkh@linuxfoundation.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> juri.lelli@redhat.com; mark.rutland@arm.com; sudeep.holla@arm.com;
> aubrey.li@linux.intel.com; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; linux-acpi@vger.kernel.org; x86@kernel.org;
> xuwei (O) <xuwei5@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> guodong.xu@linaro.org; yangyicong <yangyicong@huawei.com>; Liguozhu (Kenneth)
> <liguozhu@hisilicon.com>; linuxarm@openeuler.org; hpa@zytor.com
> Subject: Re: [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86
> 
> 
> 
> On 3/23/21 4:21 PM, Song Bao Hua (Barry Song) wrote:
> 
> >>
> >> On 3/18/21 9:16 PM, Barry Song wrote:
> >>> From: Tim Chen <tim.c.chen@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@linux.intel.com>
> >>> Signed-off-by: Barry Song <song.bao.hua@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.
> >
> 
> Barry,
> 
> This chunk will also need to be added to return cluster id for x86.
> Please add it in your next rev.

Yes. Thanks. I'll put this in either RFC v7 or Patch v1.

For spreading path, things are much easier, though packing path is 
quite tricky. But It seems RFC v6 has been quite close to what we want
to achieve to pack related tasks by scanning cluster for tasks within
same NUMA:
https://lore.kernel.org/lkml/20210420001844.9116-1-song.bao.hua@hisilicon.com/

If couples have been already in same LLC(numa), scanning clusters will
gather them further. If they are running in different NUMA nodes, the
original scanning LLC will move them to the same node, after that,
scanning cluster might put them closer to each other.

it seems it is kind of the two-level packing Dietmar has suggested.

So perhaps we won't have RFC v7, I will probably send patch v1 afterwards.

> 
> Thanks.
> 
> Tim
> 
> ---
> 
> diff --git a/arch/x86/include/asm/topology.h
> b/arch/x86/include/asm/topology.h
> index 800fa48c9fcd..2548d824f103 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -109,6 +109,7 @@ extern const struct cpumask *cpu_clustergroup_mask(int cpu);
>  #define topology_physical_package_id(cpu)	(cpu_data(cpu).phys_proc_id)
>  #define topology_logical_die_id(cpu)		(cpu_data(cpu).logical_die_id)
>  #define topology_die_id(cpu)			(cpu_data(cpu).cpu_die_id)
> +#define topology_cluster_id(cpu)		(per_cpu(cpu_l2c_id, cpu))
>  #define topology_core_id(cpu)			(cpu_data(cpu).cpu_core_id)
> 
>  extern unsigned int __max_die_per_package;

Thanks
Barry
diff mbox series

Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2792879..d597de2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1002,6 +1002,14 @@  config NR_CPUS
 	  This is purely to save memory: each supported CPU adds about 8KB
 	  to the kernel image.
 
+config SCHED_CLUSTER
+	bool "Cluster scheduler support"
+	default n
+	help
+	 Cluster scheduler support improves the CPU scheduler's decision
+	 making when dealing with machines that have clusters of CPUs
+	 sharing L2 cache. If unsure say N here.
+
 config SCHED_SMT
 	def_bool y if SMP
 
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index c0538f8..9cbc4ae 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -16,7 +16,9 @@ 
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map);
 /* cpus sharing the last level cache: */
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
+DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
 DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id);
+DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id);
 DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);
 
 static inline struct cpumask *cpu_llc_shared_mask(int cpu)
@@ -24,6 +26,11 @@  static inline struct cpumask *cpu_llc_shared_mask(int cpu)
 	return per_cpu(cpu_llc_shared_map, cpu);
 }
 
+static inline struct cpumask *cpu_l2c_shared_mask(int cpu)
+{
+	return per_cpu(cpu_l2c_shared_map, cpu);
+}
+
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid);
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid);
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid);
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 9239399..2a11ccc 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -103,6 +103,7 @@  static inline void setup_node_to_cpumask_map(void) { }
 #include <asm-generic/topology.h>
 
 extern const struct cpumask *cpu_coregroup_mask(int cpu);
+extern const struct cpumask *cpu_clustergroup_mask(int cpu);
 
 #define topology_logical_package_id(cpu)	(cpu_data(cpu).logical_proc_id)
 #define topology_physical_package_id(cpu)	(cpu_data(cpu).phys_proc_id)
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 3ca9be4..0d03a71 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -846,6 +846,7 @@  void init_intel_cacheinfo(struct cpuinfo_x86 *c)
 		l2 = new_l2;
 #ifdef CONFIG_SMP
 		per_cpu(cpu_llc_id, cpu) = l2_id;
+		per_cpu(cpu_l2c_id, cpu) = l2_id;
 #endif
 	}
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ab640ab..0ba282d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -78,6 +78,9 @@ 
 /* Last level cache ID of each logical CPU */
 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID;
 
+/* L2 cache ID of each logical CPU */
+DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id) = BAD_APICID;
+
 /* correctly size the local cpu masks */
 void __init setup_cpu_local_masks(void)
 {
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 02813a7..c85ffa8 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -101,6 +101,8 @@ 
 
 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
 
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
+
 /* Per CPU bogomips and other parameters */
 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
 EXPORT_PER_CPU_SYMBOL(cpu_info);
@@ -501,6 +503,21 @@  static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 	return topology_sane(c, o, "llc");
 }
 
+static bool match_l2c(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+
+	/* Do not match if we do not have a valid APICID for cpu: */
+	if (per_cpu(cpu_l2c_id, cpu1) == BAD_APICID)
+		return false;
+
+	/* Do not match if L2 cache id does not match: */
+	if (per_cpu(cpu_l2c_id, cpu1) != per_cpu(cpu_l2c_id, cpu2))
+		return false;
+
+	return topology_sane(c, o, "l2c");
+}
+
 /*
  * Unlike the other levels, we do not enforce keeping a
  * multicore group inside a NUMA node.  If this happens, we will
@@ -522,7 +539,7 @@  static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 }
 
 
-#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
+#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_CLUSTER) || defined(CONFIG_SCHED_MC)
 static inline int x86_sched_itmt_flags(void)
 {
 	return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
@@ -540,12 +557,21 @@  static int x86_smt_flags(void)
 	return cpu_smt_flags() | x86_sched_itmt_flags();
 }
 #endif
+#ifdef CONFIG_SCHED_CLUSTER
+static int x86_cluster_flags(void)
+{
+	return cpu_cluster_flags() | x86_sched_itmt_flags();
+}
+#endif
 #endif
 
 static struct sched_domain_topology_level x86_numa_in_package_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
 #endif
+#ifdef CONFIG_SCHED_CLUSTER
+	{ cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS) },
+#endif
 #ifdef CONFIG_SCHED_MC
 	{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
 #endif
@@ -556,6 +582,9 @@  static int x86_smt_flags(void)
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
 #endif
+#ifdef CONFIG_SCHED_CLUSTER
+	{ cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS) },
+#endif
 #ifdef CONFIG_SCHED_MC
 	{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
 #endif
@@ -583,6 +612,7 @@  void set_cpu_sibling_map(int cpu)
 	if (!has_mp) {
 		cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
 		cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
+		cpumask_set_cpu(cpu, cpu_l2c_shared_mask(cpu));
 		cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
 		cpumask_set_cpu(cpu, topology_die_cpumask(cpu));
 		c->booted_cores = 1;
@@ -598,6 +628,8 @@  void set_cpu_sibling_map(int cpu)
 		if ((i == cpu) || (has_mp && match_llc(c, o)))
 			link_mask(cpu_llc_shared_mask, cpu, i);
 
+		if ((i == cpu) || (has_mp && match_l2c(c, o)))
+			link_mask(cpu_l2c_shared_mask, cpu, i);
 	}
 
 	/*
@@ -649,6 +681,11 @@  const struct cpumask *cpu_coregroup_mask(int cpu)
 	return cpu_llc_shared_mask(cpu);
 }
 
+const struct cpumask *cpu_clustergroup_mask(int cpu)
+{
+	return cpu_l2c_shared_mask(cpu);
+}
+
 static void impress_friends(void)
 {
 	int cpu;
@@ -1332,6 +1369,7 @@  void __init native_smp_prepare_cpus(unsigned int max_cpus)
 		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
 		zalloc_cpumask_var(&per_cpu(cpu_die_map, i), GFP_KERNEL);
 		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_l2c_shared_map, i), GFP_KERNEL);
 	}
 
 	/*
@@ -1556,7 +1594,10 @@  static void remove_siblinginfo(int cpu)
 		cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
 	for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
 		cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
+	for_each_cpu(sibling, cpu_l2c_shared_mask(cpu))
+		cpumask_clear_cpu(cpu, cpu_l2c_shared_mask(sibling));
 	cpumask_clear(cpu_llc_shared_mask(cpu));
+	cpumask_clear(cpu_l2c_shared_mask(cpu));
 	cpumask_clear(topology_sibling_cpumask(cpu));
 	cpumask_clear(topology_core_cpumask(cpu));
 	cpumask_clear(topology_die_cpumask(cpu));