- Linaro-open-discussions - op-lists.linaro.org

Re: [Linaro-open-discussions] Meeting on July 23rd

by Jammy Zhou

Hi all, The notes have been published on the meeting page below together with the slides and video. Thanks Alex and Jonathan for the great presentations. https://linaro.atlassian.net/wiki/spaces/LOD/pages/28544303418/2021-07-23+M… Regards, Jammy On Wed, 21 Jul 2021 at 23:16, Jammy Zhou via Linaro-open-discussions < linaro-open-discussions(a)op-lists.linaro.org> wrote: > Hi all, > > Just a kind reminder that the LOD meeting in July has been rescheduled to > 23rd, Friday this week. > > In this meeting, we will have a good topic from Alex Bennée to > introduce QEMU 6.1 and future work. > > Please let me know if you have any other topics. > > Thanks, > Jammy > -- > Linaro-open-discussions mailing list > https://collaborate.linaro.org/display/LOD/Linaro+Open+Discussions+Home > https://op-lists.linaro.org/mailman/listinfo/linaro-open-discussions >

4 years

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Re: [Linaro-open-discussions] [PATCH 1/4] sched: Add infrastructure to describe if cluster scheduler is really running

by Tim Chen

On 7/22/21 1:37 PM, Song Bao Hua (Barry Song) wrote: > Regarding squashing scheduler level, what you say is true. However, > as long as we are changing code based on if(sched_cluster_present) > in wake_affine path, we need to care about this. I'm wondering if we can use SD_CLUSTER flag I introduced in my patch 2 sent yesterday to determine if we have a cluster sched domain instead of sched_cluster_present? So if we squash the cluster sched domain we'll skip the logic for the sched domain, instead of having a global flag. > >> If the CLS domain equals the MC domain, finally the CLS will stay and >> MC will be destroyed. Nothing need to do then. If the CLS domain equals >> the SMT domain, SMT will stay and we need to modify the >> @sched_cluster_present then. But I doubt whether there is a real case >> than CLS will be the same as SMT. > > It doesn't matter if there is a real hardware. What does matter is > how the topology patch(patch 1) will parse ACPI table and whether > ACPI has a particular flag for cluster. > > Thanks > Barry >

4 years

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[PATCH 0/3] Add run time sysctl to enable/disable cluster scheduling

by Tim Chen

Barry & Yicong, I've added this series to allow for run time control of cluster scheduling via /proc/sys/kernel/sched_cluster_enabled. I've defaulted the setting to off as this is probably the safest option and will encounter the least resistance. I've also added a SD_CLUSTER flag in patch 2. It may be handy if we want to do any cluster specific scheduling operation in a cluster sched domain. This could be a follow on after the main patchset is posted. I've tested it on my x86 machine. Wonder if you can test it on your ARM system to make sure it works properly there. Will appreciate your feedback and review. Tim Tim Chen (3): sched: Create SDTL_SKIP flag to skip topology level sched: Add SD_CLUSTER topology flag to cluster sched domain sched: Add runtime knob sysctl_sched_cluster_enabled arch/x86/kernel/smpboot.c | 8 +++++ drivers/base/arch_topology.c | 7 ++++ include/linux/sched/sd_flags.h | 7 ++++ include/linux/sched/sysctl.h | 6 ++++ include/linux/sched/topology.h | 3 +- include/linux/topology.h | 7 ++++ kernel/sched/core.c | 1 + kernel/sched/sched.h | 6 ++++ kernel/sched/topology.c | 58 +++++++++++++++++++++++++++++++++- kernel/sysctl.c | 11 +++++++ 10 files changed, 112 insertions(+), 2 deletions(-) -- 2.20.1

4 years, 1 month

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LOC Monthly Meeting - Thursday July 22

by Ruchika Gupta

Hi, LOC (Linaro OP-TEE Contribution) monthly meeting is planned to take place on Thursday July22(a)17.00 (UTC+2). Looking for topics from people. If you have anything you'd like to discuss, please let us know. Meeting details: --------------- Date/time: Thursday Jul22(a)17.00 (UTC+2) https://everytimezone.com/s/d926310d Connection details: https://www.trustedfirmware.org/meetings/ Meeting notes: http://bit.ly/loc-notes Regards, Ruchika on behalf of the Linaro OP-TEE team

4 years, 1 month

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Meeting on July 23rd

by Jammy Zhou

Hi all, Just a kind reminder that the LOD meeting in July has been rescheduled to 23rd, Friday this week. In this meeting, we will have a good topic from Alex Bennée to introduce QEMU 6.1 and future work. Please let me know if you have any other topics. Thanks, Jammy

4 years, 1 month

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Re: [Linaro-open-discussions] LOD Meeting Agenda for June 28

by Lorenzo Pieralisi

On Tue, Jul 06, 2021 at 02:21:16PM +0000, Lorenzo Pieralisi via Linaro-open-discussions wrote: > On Wed, Jun 23, 2021 at 01:10:52PM +0000, Jonathan Cameron via Linaro-open-discussions wrote: > > On Tue, 22 Jun 2021 12:17:33 +0000 > > Jonathan Cameron via Linaro-open-discussions <linaro-open-discussions(a)op-lists.linaro.org> wrote: > > > > > On Tue, 22 Jun 2021 09:39:15 +0000 > > > Lorenzo Pieralisi via Linaro-open-discussions <linaro-open-discussions(a)op-lists.linaro.org> wrote: > > > > > > > On Mon, Jun 21, 2021 at 09:33:42PM +0000, Song Bao Hua (Barry Song) wrote: > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: Linaro-open-discussions > > > > > > [mailto:linaro-open-discussions-bounces@op-lists.linaro.org] On Behalf Of > > > > > > Lorenzo Pieralisi via Linaro-open-discussions > > > > > > Sent: Monday, June 21, 2021 9:32 PM > > > > > > To: Jammy Zhou <jammy.zhou(a)linaro.org> > > > > > > Cc: Lorenzo Pieralisi via Linaro-open-discussions > > > > > > <linaro-open-discussions(a)op-lists.linaro.org> > > > > > > Subject: Re: [Linaro-open-discussions] LOD Meeting Agenda for June 28 > > > > > > > > > > > > On Mon, Jun 21, 2021 at 12:37:03AM +0000, Jammy Zhou via Linaro-open-discussions > > > > > > wrote: > > > > > > > Hi all, > > > > > > > > > > > > > > We are only one week away from the next LOD meeting on June 28. If you > > > > > > > have any topic to discuss, please let me know. > > > > > > > > > > > > We could discuss the virt CPU hotplug status/forward plan. > > > > > > > > > > > > I don't know if Barry's scheduler discussion can benefit from an LOD > > > > > > session, please chime in if that's the case. > > > > > > > > > > Hi Lorenzo, > > > > > Thanks for asking. I have no important updates at this time. That > > > > > discussion is mainly for co-working with Tim Chen on the plan of > > > > > upstreaming and benchmarking, also figuring out whether the patches > > > > > are leading to the same result on arm and x86 platforms. > > > > > > > > > > > > > > > > > AOB ? > > > > > > > > Ok. So, anything else to discuss other than the PSCI KVM patches > > > > that are currently on ML ? Jonathan, Salil, anyone please do let > > > > me know. > > > > > > > > > > On the near term horizon is the confidential compute stuff that there > > > is an event about tomorrow, but next week feels a little early to try > > > and have a detailed discussion about that (I assume)? > > > > > > A few other things will surface by next month, but not next week ;) > > > > > > Otherwise, nothing immediate jumps out to me, beyond any useful > > > discussion that can be had around the PSCI KVM patches you mention. > > > > > > Thanks, > > > > > > Jonathan > > > > > > > Leaving that one aside, it seems the main open question from our side > > is around planning / progress on steps for the vCPU hotplug. > > > > Perhaps that's something best formulated over email... > > > > My current understanding is that next item would be the Guest Kernel > > changes? Perhaps a good target for sending out an RFC on that would > > be just after the merge window? > > I am afraid we will have to rework the approach and implement this > through ACPI only (kernel/spec changes) which is both good and bad news. > > I am focusing on getting the ACPI specs agreed/changed in the Arm world, > it will take me a while, hopefully I can expedite, that's all I can > share here. Next week I should be able to let you know what we are pursuing going forward, it is just to let you know that we are working on it to converge as soon as possible. The end result should not be massively different from Salil's initial work but there are lots of details we are vetting to make sure it is rock solid (and that everyone in the ARM world is happy with it, again, I can't share the fine grain details here). Have a good week end, Lorenzo

4 years, 1 month

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Propose QEMU 6.1 and future work as a topic for LOD sync-up on 26th July

by Alex Bennée

Hi, The QEMU project will have tagged rc0 on the 20th so we will know with a fair bit of certainty the features that will make it into 6.1. We'll also be transitioning from our Connect->Connect 6 month planning cycle to the upstream aligned planning. There will be one more QEMU release this year which will be 6.2. I propose to present the following: - what made it into 6.1 - what we are aiming to get into 6.2 - what we are thinking about next There have been some fairly big ARM features announced recently so I'd like to cover the teams initial thoughts about what would be needed to successfully upstream things like CCA and SME. It's intended to be a collaborative call so please come with questions and discussion points. We are a small team so we aim to be a force multiplier for collaboration ;-) -- Alex Bennée

4 years, 1 month

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Re: [Linaro-open-discussions] LOD Meeting Agenda for June 28

by Lorenzo Pieralisi

On Wed, Jun 23, 2021 at 01:10:52PM +0000, Jonathan Cameron via Linaro-open-discussions wrote: > On Tue, 22 Jun 2021 12:17:33 +0000 > Jonathan Cameron via Linaro-open-discussions <linaro-open-discussions(a)op-lists.linaro.org> wrote: > > > On Tue, 22 Jun 2021 09:39:15 +0000 > > Lorenzo Pieralisi via Linaro-open-discussions <linaro-open-discussions(a)op-lists.linaro.org> wrote: > > > > > On Mon, Jun 21, 2021 at 09:33:42PM +0000, Song Bao Hua (Barry Song) wrote: > > > > > > > > > > > > > -----Original Message----- > > > > > From: Linaro-open-discussions > > > > > [mailto:linaro-open-discussions-bounces@op-lists.linaro.org] On Behalf Of > > > > > Lorenzo Pieralisi via Linaro-open-discussions > > > > > Sent: Monday, June 21, 2021 9:32 PM > > > > > To: Jammy Zhou <jammy.zhou(a)linaro.org> > > > > > Cc: Lorenzo Pieralisi via Linaro-open-discussions > > > > > <linaro-open-discussions(a)op-lists.linaro.org> > > > > > Subject: Re: [Linaro-open-discussions] LOD Meeting Agenda for June 28 > > > > > > > > > > On Mon, Jun 21, 2021 at 12:37:03AM +0000, Jammy Zhou via Linaro-open-discussions > > > > > wrote: > > > > > > Hi all, > > > > > > > > > > > > We are only one week away from the next LOD meeting on June 28. If you > > > > > > have any topic to discuss, please let me know. > > > > > > > > > > We could discuss the virt CPU hotplug status/forward plan. > > > > > > > > > > I don't know if Barry's scheduler discussion can benefit from an LOD > > > > > session, please chime in if that's the case. > > > > > > > > Hi Lorenzo, > > > > Thanks for asking. I have no important updates at this time. That > > > > discussion is mainly for co-working with Tim Chen on the plan of > > > > upstreaming and benchmarking, also figuring out whether the patches > > > > are leading to the same result on arm and x86 platforms. > > > > > > > > > > > > > > AOB ? > > > > > > Ok. So, anything else to discuss other than the PSCI KVM patches > > > that are currently on ML ? Jonathan, Salil, anyone please do let > > > me know. > > > > > > > On the near term horizon is the confidential compute stuff that there > > is an event about tomorrow, but next week feels a little early to try > > and have a detailed discussion about that (I assume)? > > > > A few other things will surface by next month, but not next week ;) > > > > Otherwise, nothing immediate jumps out to me, beyond any useful > > discussion that can be had around the PSCI KVM patches you mention. > > > > Thanks, > > > > Jonathan > > > > Leaving that one aside, it seems the main open question from our side > is around planning / progress on steps for the vCPU hotplug. > > Perhaps that's something best formulated over email... > > My current understanding is that next item would be the Guest Kernel > changes? Perhaps a good target for sending out an RFC on that would > be just after the merge window? I am afraid we will have to rework the approach and implement this through ACPI only (kernel/spec changes) which is both good and bad news. I am focusing on getting the ACPI specs agreed/changed in the Arm world, it will take me a while, hopefully I can expedite, that's all I can share here. Lorenzo

4 years, 1 month

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Re: [Linaro-open-discussions] [PATCH 4/4] sched/fair: Use cpus_share_cluster to further pull wakee

by Song Bao Hua (Barry Song)

> -----Original Message----- > From: Tim Chen [mailto:tim.c.chen@linux.intel.com] > Sent: Friday, June 25, 2021 1:00 PM > To: Song Bao Hua (Barry Song) <song.bao.hua(a)hisilicon.com>; yangyicong > <yangyicong(a)huawei.com> > Cc: guodong.xu(a)linaro.org; tangchengchang <tangchengchang(a)huawei.com>; > Zengtao (B) <prime.zeng(a)hisilicon.com>; Jonathan Cameron > <jonathan.cameron(a)huawei.com>; chenxiang (M) <chenxiang66(a)hisilicon.com>; > Linuxarm <linuxarm(a)huawei.com> > Subject: Re: [PATCH 4/4] sched/fair: Use cpus_share_cluster to further pull > wakee > > > > On 6/24/21 2:15 AM, Barry Song wrote: > > In wake_affine_idle() and select_idle_sibling(), move to use > > cpus_share_cluster() rather than cpus_share_cache() to > > determine if waker and wakee are in same cache domain. > > This patch mainly benefits light load system. > > > > we are seeing a huge improvement while load is relatively light: > > (1numa, 24cores, 6 clusters) > > tbench4 > > tbench tbench > > 1numa-w/-cluster-spread-only > 1numa-w-cluster-spread+scancluster+cpus_share_cluster > > Hmean 1 297.22 ( 0.00%) 331.31 * 11.47%* > > Hmean 2 597.33 ( 0.00%) 661.35 * 10.72%* > > Hmean 4 1211.53 ( 0.00%) 1317.34 * 8.73%* > > Hmean 8 2465.05 ( 0.00%) 2612.18 * 5.97%* > > Hmean 16 3194.06 ( 0.00%) 4089.96 * 28.05%* > > Hmean 32 5984.82 ( 0.00%) 6374.53 * 6.51%* > > Hmean 64 5017.10 ( 0.00%) 5255.47 * 4.75%* > > Hmean 96 4705.88 ( 0.00%) 4860.40 * 3.28%* > > > > With this patch, tbench4 is getting better than w/o cluster for both > > light load and heavy load: > > > > tbench4 > > tbench tbench > > 1numa-w/o-cluster > 1numa-w-cluster-spread+scancluster+cpus_share_cluster > > Hmean 1 314.11 ( 0.00%) 331.31 * 5.47%* > > Hmean 2 612.83 ( 0.00%) 661.35 * 7.92%* > > Hmean 4 1232.90 ( 0.00%) 1317.34 * 6.85%* > > Hmean 8 2470.26 ( 0.00%) 2612.18 * 5.74%* > > Hmean 16 3203.89 ( 0.00%) 4089.96 * 27.66%* > > Hmean 32 6210.83 ( 0.00%) 6374.53 * 2.64%* > > Hmean 64 5053.54 ( 0.00%) 5255.47 * 4.00%* > > Hmean 96 4726.44 ( 0.00%) 4860.40 * 2.83%* > > > > [ > > Todo: > > need pgbench, hackbench on 1numa, 4numa; need tbench4 on 4numa > > ] > > > > Signed-off-by: Barry Song <song.bao.hua(a)hisilicon.com> > > --- > > kernel/sched/core.c | 5 ++++- > > kernel/sched/fair.c | 6 +++--- > > 2 files changed, 7 insertions(+), 4 deletions(-) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 47a4c82..6cfb0fa 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -3504,7 +3504,10 @@ bool cpus_share_cache(int this_cpu, int that_cpu) > > > > bool cpus_share_cluster(int this_cpu, int that_cpu) > > { > > - return per_cpu(sd_cluster_id, this_cpu) == per_cpu(sd_cluster_id, > that_cpu); > > + if(sched_cluster_active()) > > + return per_cpu(sd_cluster_id, this_cpu) == per_cpu(sd_cluster_id, > that_cpu); > > + > > + return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); > > Nitpicking a bit. When sched_cluster is inactive is not active, we are > really comparing the last level cache. Wonder if we can give cpus_share_cluster > a better > name as we will return true in this case when the cpus are not in same cluster. > Yes. A little bit ugly here. I used to add a parameter in cpus_share_cache(cpux,cpuy,cluster) in RFC patchset. If cluster is 0, we compare LLC; if cluster is 1, we compare cluster. And I feel it made cpus_share_cache() more obscure. So I add cpus_share_cluster(cpux,cpuy) but it is also not perfect. Might add an internal function in fair.c: static bool cpus_share_wake_affine_cache(cpux, cpuy) { if(cluster is active) return cpus_share_cluster(cpux,cpuy); else return cpus_share_cache(cpux,cpuy); } And remove the " if(cluster is active)" in current cpus_share_cluster()? BTW, Tim, I am curious if your machine will get same tbench4 result with kunpeng920. I am using https://github.com/gormanm/mmtests and command like: run-mmtests.sh --no-monitor -c configs/config-network-tbench-quick testtag1 run-mmtests.sh --no-monitor -c configs/config-network-tbench-quick testtag2 cd work/log ../../compare-kernels.sh --baseline testtag1 --compare testtag2 > > } > > > > static inline bool ttwu_queue_cond(int cpu, int wake_flags) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index fdc2cf8..41ebbf2 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -5797,7 +5797,7 @@ static int wake_wide(struct task_struct *p) > > * a cpufreq perspective, it's better to have higher utilisation > > * on one CPU. > > */ > > - if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu)) > > + if (available_idle_cpu(this_cpu) && cpus_share_cluster(this_cpu, > prev_cpu)) > > return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu; > > > > if (sync && cpu_rq(this_cpu)->nr_running == 1) > > @@ -6297,7 +6297,7 @@ static int select_idle_sibling(struct task_struct *p, > int prev, int target) > > /* > > * If the previous CPU is cache affine and idle, don't be stupid: > > */ > > - if (prev != target && cpus_share_cache(prev, target) && > > + if (prev != target && cpus_share_cluster(prev, target) && > > (available_idle_cpu(prev) || sched_idle_cpu(prev)) && > > asym_fits_capacity(task_util, prev)) > > return prev; > > @@ -6320,7 +6320,7 @@ static int select_idle_sibling(struct task_struct *p, > int prev, int target) > > recent_used_cpu = p->recent_used_cpu; > > if (recent_used_cpu != prev && > > recent_used_cpu != target && > > - cpus_share_cache(recent_used_cpu, target) && > > + cpus_share_cluster(recent_used_cpu, target) && > > (available_idle_cpu(recent_used_cpu) || > sched_idle_cpu(recent_used_cpu)) && > > cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) && > > asym_fits_capacity(task_util, recent_used_cpu)) { > > Thanks Barry

4 years, 1 month

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Re: [Linaro-open-discussions] [PATCH 1/4] sched: Add infrastructure to describe if cluster scheduler is really running

by Song Bao Hua (Barry Song)

> -----Original Message----- > From: Tim Chen [mailto:tim.c.chen@linux.intel.com] > Sent: Friday, June 25, 2021 11:03 AM > To: Song Bao Hua (Barry Song) <song.bao.hua(a)hisilicon.com>; yangyicong > <yangyicong(a)huawei.com> > Cc: guodong.xu(a)linaro.org; tangchengchang <tangchengchang(a)huawei.com>; > Zengtao (B) <prime.zeng(a)hisilicon.com>; Jonathan Cameron > <jonathan.cameron(a)huawei.com>; chenxiang (M) <chenxiang66(a)hisilicon.com>; > Linuxarm <linuxarm(a)huawei.com> > Subject: Re: [PATCH 1/4] sched: Add infrastructure to describe if cluster > scheduler is really running > > > > On 6/24/21 2:15 AM, Barry Song wrote: > > use sched_cluster_present static key to describe if cluster scheduler > > is really working. > > and add sched_cluster_active() API to reflect the status of cluster > > scheduler as well. > > Only if cluster is bigger than smt, and less than coregroup, we are > > quite sure cluster scheduler is used. > > > > Signed-off-by: Barry Song <song.bao.hua(a)hisilicon.com> > > --- > > include/linux/sched/cluster.h | 19 +++++++++++++++++++ > > kernel/sched/core.c | 20 ++++++++++++++++++++ > > kernel/sched/fair.c | 4 ++++ > > kernel/sched/sched.h | 1 + > > 4 files changed, 44 insertions(+) > > create mode 100644 include/linux/sched/cluster.h > > > > diff --git a/include/linux/sched/cluster.h b/include/linux/sched/cluster.h > > new file mode 100644 > > index 0000000..ea6c475 > > --- /dev/null > > +++ b/include/linux/sched/cluster.h > > @@ -0,0 +1,19 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +#ifndef _LINUX_SCHED_CLUSTER_H > > +#define _LINUX_SCHED_CLUSTER_H > > + > > +#include <linux/static_key.h> > > + > > +#ifdef CONFIG_SCHED_CLUSTER > > +extern struct static_key_false sched_cluster_present; > > + > > +static __always_inline bool sched_cluster_active(void) > > +{ > > + return static_branch_likely(&sched_cluster_present); > > Barry, we may encounter load where having the cluster sched > domain is not productive. Wonder if we should add a run time > sysfs control to turn on/off the sched cluster feature (for packing) > and cluster sched domain (for spreading). > > This is a bit orthogonal to this patch series but could be > a 3rd patchset. We may try though I am not sure if Peter is a fan of this kind of sysctl. This kind of thing is usually done by sched_feat(): There is a sysfs_feature ctl in /sys/kernel/debug/sched/features: kernel/sched/debug.c static int sched_feat_set(char *cmp) { int i; int neg = 0; if (strncmp(cmp, "NO_", 3) == 0) { neg = 1; cmp += 3; } i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp); if (i < 0) return i; if (neg) { sysctl_sched_features &= ~(1UL << i); sched_feat_disable(i); } else { sysctl_sched_features |= (1UL << i); sched_feat_enable(i); } return 0; } > > Tim > > > +} > > +#else > > +static inline bool sched_cluster_active(void) { return false; } > > + > > +#endif > > + > > +#endif > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 9e9a5be..dd5984d 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -8655,6 +8655,17 @@ int sched_cpu_activate(unsigned int cpu) > > if (cpumask_weight(cpu_smt_mask(cpu)) == 2) > > static_branch_inc_cpuslocked(&sched_smt_present); > > #endif > > + > > +#ifdef CONFIG_SCHED_CLUSTER > > + /* > > + * When going up, increment the number of cluster cpus with > > + * cluster present. > > + */ > > + if (cpumask_weight(cpu_cluster_mask(cpu)) > > cpumask_weight(cpu_smt_mask(cpu)) && > > + cpumask_weight(cpu_cluster_mask(cpu)) < > cpumask_weight(cpu_coregroup_mask(cpu))) > > + static_branch_inc_cpuslocked(&sched_cluster_present); > > +#endif > > + > > set_cpu_active(cpu, true); > > > > if (sched_smp_initialized) { > > @@ -8731,6 +8742,15 @@ int sched_cpu_deactivate(unsigned int cpu) > > static_branch_dec_cpuslocked(&sched_smt_present); > > #endif > > > > +#ifdef CONFIG_SCHED_CLUSTER > > + /* > > + * When going down, decrement the number of cpus with cluster present. > > + */ > > + if (cpumask_weight(cpu_cluster_mask(cpu)) > > cpumask_weight(cpu_smt_mask(cpu)) && > > + cpumask_weight(cpu_cluster_mask(cpu)) < > cpumask_weight(cpu_coregroup_mask(cpu))) > > + static_branch_dec_cpuslocked(&sched_cluster_present); > > +#endif > > + > > if (!sched_smp_initialized) > > return 0; > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index ce625bf..8578cb1 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -5997,6 +5997,10 @@ static inline int __select_idle_cpu(int cpu, struct > task_struct *p) > > return -1; > > } > > > > +#ifdef CONFIG_SCHED_CLUSTER > > +DEFINE_STATIC_KEY_FALSE(sched_cluster_present); > > +#endif > > + > > #ifdef CONFIG_SCHED_SMT > > DEFINE_STATIC_KEY_FALSE(sched_smt_present); > > EXPORT_SYMBOL_GPL(sched_smt_present); > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > > index 8f0194c..0f8f610 100644 > > --- a/kernel/sched/sched.h > > +++ b/kernel/sched/sched.h > > @@ -6,6 +6,7 @@ > > > > #include <linux/sched/autogroup.h> > > #include <linux/sched/clock.h> > > +#include <linux/sched/cluster.h> > > #include <linux/sched/coredump.h> > > #include <linux/sched/cpufreq.h> > > #include <linux/sched/cputime.h> > > Thanks Barry

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