From: Barry Song <song.bao.hua@hisilicon.com>
For platforms having clusters like Kunpeng920, CPUs within the same cluster
have lower latency when synchronizing and accessing shared resources like
cache. Thus, this patch tries to find an idle cpu within the cluster of the
target CPU before scanning the whole LLC to gain lower latency.
Testing has been done on Kunpeng920 by pinning tasks to one numa and two
numa. On Kunpeng920, Each numa has 8 clusters and each cluster has 4 CPUs.
With this patch, We noticed enhancement on tbench within one numa or cross
two numa.
On numa 0:
6.0-rc1 patched
Hmean 1 351.20 ( 0.00%) 396.45 * 12.88%*
Hmean 2 700.43 ( 0.00%) 793.76 * 13.32%*
Hmean 4 1404.42 ( 0.00%) 1583.62 * 12.76%*
Hmean 8 2833.31 ( 0.00%) 3147.85 * 11.10%*
Hmean 16 5501.90 ( 0.00%) 6089.89 * 10.69%*
Hmean 32 10428.59 ( 0.00%) 10619.63 * 1.83%*
Hmean 64 8223.39 ( 0.00%) 8306.93 * 1.02%*
Hmean 128 7042.88 ( 0.00%) 7068.03 * 0.36%*
On numa 0-1:
6.0-rc1 patched
Hmean 1 363.06 ( 0.00%) 397.13 * 9.38%*
Hmean 2 721.68 ( 0.00%) 789.84 * 9.44%*
Hmean 4 1435.15 ( 0.00%) 1566.01 * 9.12%*
Hmean 8 2776.17 ( 0.00%) 3007.05 * 8.32%*
Hmean 16 5471.71 ( 0.00%) 6103.91 * 11.55%*
Hmean 32 10164.98 ( 0.00%) 11531.81 * 13.45%*
Hmean 64 17143.28 ( 0.00%) 20078.68 * 17.12%*
Hmean 128 14552.70 ( 0.00%) 15156.41 * 4.15%*
Hmean 256 12827.37 ( 0.00%) 13326.86 * 3.89%*
Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so the SMT branch
in the code has not been tested but it supposed to work.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
[https://lore.kernel.org/lkml/Ytfjs+m1kUs0ScSn@worktop.programming.kicks-ass.net]
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
---
kernel/sched/fair.c | 30 +++++++++++++++++++++++++++---
kernel/sched/sched.h | 2 ++
kernel/sched/topology.c | 10 ++++++++++
3 files changed, 39 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 914096c5b1ae..6fa77610d0f5 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6437,6 +6437,30 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
}
}
+ if (static_branch_unlikely(&sched_cluster_active)) {
+ struct sched_domain *sdc = rcu_dereference(per_cpu(sd_cluster, target));
+
+ if (sdc) {
+ for_each_cpu_wrap(cpu, sched_domain_span(sdc), target + 1) {
+ if (!cpumask_test_cpu(cpu, cpus))
+ continue;
+
+ if (has_idle_core) {
+ i = select_idle_core(p, cpu, cpus, &idle_cpu);
+ if ((unsigned int)i < nr_cpumask_bits)
+ return i;
+ } else {
+ if (--nr <= 0)
+ return -1;
+ idle_cpu = __select_idle_cpu(cpu, p);
+ if ((unsigned int)idle_cpu < nr_cpumask_bits)
+ return idle_cpu;
+ }
+ }
+ cpumask_andnot(cpus, cpus, sched_domain_span(sdc));
+ }
+ }
+
for_each_cpu_wrap(cpu, cpus, target + 1) {
if (has_idle_core) {
i = select_idle_core(p, cpu, cpus, &idle_cpu);
@@ -6444,7 +6468,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
return i;
} else {
- if (!--nr)
+ if (--nr <= 0)
return -1;
idle_cpu = __select_idle_cpu(cpu, p);
if ((unsigned int)idle_cpu < nr_cpumask_bits)
@@ -6543,7 +6567,7 @@ 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_lowest_cache(prev, target) &&
(available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
asym_fits_capacity(task_util, prev))
return prev;
@@ -6569,7 +6593,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
p->recent_used_cpu = prev;
if (recent_used_cpu != prev &&
recent_used_cpu != target &&
- cpus_share_cache(recent_used_cpu, target) &&
+ cpus_share_lowest_cache(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)) {
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e9f0935605e2..60e8a91e29d1 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1815,7 +1815,9 @@ DECLARE_PER_CPU(struct sched_domain __rcu *, sd_cluster);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+
extern struct static_key_false sched_asym_cpucapacity;
+extern struct static_key_false sched_cluster_active;
struct sched_group_capacity {
atomic_t ref;
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 8ab27c0d6d1f..04ead3227201 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -670,7 +670,9 @@ DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
+DEFINE_STATIC_KEY_FALSE(sched_cluster_active);
static void update_top_cache_domain(int cpu)
{
@@ -2268,6 +2270,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
struct rq *rq = NULL;
int i, ret = -ENOMEM;
bool has_asym = false;
+ bool has_cluster = false;
if (WARN_ON(cpumask_empty(cpu_map)))
goto error;
@@ -2289,6 +2292,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
sd = build_sched_domain(tl, cpu_map, attr, sd, i);
has_asym |= sd->flags & SD_ASYM_CPUCAPACITY;
+ has_cluster |= sd->flags & SD_CLUSTER;
if (tl == sched_domain_topology)
*per_cpu_ptr(d.sd, i) = sd;
@@ -2399,6 +2403,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
if (has_asym)
static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
+ if (has_cluster)
+ static_branch_inc_cpuslocked(&sched_cluster_active);
+
if (rq && sched_debug_verbose) {
pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
@@ -2498,6 +2505,9 @@ static void detach_destroy_domains(const struct cpumask *cpu_map)
if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu)))
static_branch_dec_cpuslocked(&sched_asym_cpucapacity);
+ if (rcu_access_pointer(per_cpu(sd_cluster, cpu)))
+ static_branch_dec_cpuslocked(&sched_cluster_active);
+
rcu_read_lock();
for_each_cpu(i, cpu_map)
cpu_attach_domain(NULL, &def_root_domain, i);
--
2.24.0On 2022-08-22 at 15:36:10 +0800, Yicong Yang wrote:
> From: Barry Song <song.bao.hua@hisilicon.com>
>
> For platforms having clusters like Kunpeng920, CPUs within the same cluster
> have lower latency when synchronizing and accessing shared resources like
> cache. Thus, this patch tries to find an idle cpu within the cluster of the
> target CPU before scanning the whole LLC to gain lower latency.
>
> Testing has been done on Kunpeng920 by pinning tasks to one numa and two
> numa. On Kunpeng920, Each numa has 8 clusters and each cluster has 4 CPUs.
>
> With this patch, We noticed enhancement on tbench within one numa or cross
> two numa.
>
> On numa 0:
> 6.0-rc1 patched
> Hmean 1 351.20 ( 0.00%) 396.45 * 12.88%*
> Hmean 2 700.43 ( 0.00%) 793.76 * 13.32%*
> Hmean 4 1404.42 ( 0.00%) 1583.62 * 12.76%*
> Hmean 8 2833.31 ( 0.00%) 3147.85 * 11.10%*
> Hmean 16 5501.90 ( 0.00%) 6089.89 * 10.69%*
> Hmean 32 10428.59 ( 0.00%) 10619.63 * 1.83%*
> Hmean 64 8223.39 ( 0.00%) 8306.93 * 1.02%*
> Hmean 128 7042.88 ( 0.00%) 7068.03 * 0.36%*
>
> On numa 0-1:
> 6.0-rc1 patched
> Hmean 1 363.06 ( 0.00%) 397.13 * 9.38%*
> Hmean 2 721.68 ( 0.00%) 789.84 * 9.44%*
> Hmean 4 1435.15 ( 0.00%) 1566.01 * 9.12%*
> Hmean 8 2776.17 ( 0.00%) 3007.05 * 8.32%*
> Hmean 16 5471.71 ( 0.00%) 6103.91 * 11.55%*
> Hmean 32 10164.98 ( 0.00%) 11531.81 * 13.45%*
> Hmean 64 17143.28 ( 0.00%) 20078.68 * 17.12%*
> Hmean 128 14552.70 ( 0.00%) 15156.41 * 4.15%*
> Hmean 256 12827.37 ( 0.00%) 13326.86 * 3.89%*
>
> Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so the SMT branch
> in the code has not been tested but it supposed to work.
>
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> [https://lore.kernel.org/lkml/Ytfjs+m1kUs0ScSn@worktop.programming.kicks-ass.net]
> Tested-by: Yicong Yang <yangyicong@hisilicon.com>
> Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
> ---
> kernel/sched/fair.c | 30 +++++++++++++++++++++++++++---
> kernel/sched/sched.h | 2 ++
> kernel/sched/topology.c | 10 ++++++++++
> 3 files changed, 39 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 914096c5b1ae..6fa77610d0f5 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -6437,6 +6437,30 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
> }
> }
>
> + if (static_branch_unlikely(&sched_cluster_active)) {
> + struct sched_domain *sdc = rcu_dereference(per_cpu(sd_cluster, target));
> +
> + if (sdc) {
> + for_each_cpu_wrap(cpu, sched_domain_span(sdc), target + 1) {
Looks good to me. One minor question, why don't we use
cpumask_and(cpus, sched_domain_span(sdc), cpus);
> + if (!cpumask_test_cpu(cpu, cpus))
> + continue;
so above check can be removed in each loop? Besides may I know what version this patch
is based on? since I failed to apply the patch on v6.0-rc2. Other than that:
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
thanks,
Chenyu
> +
> + if (has_idle_core) {
> + i = select_idle_core(p, cpu, cpus, &idle_cpu);
> + if ((unsigned int)i < nr_cpumask_bits)
> + return i;
> + } else {
> + if (--nr <= 0)
> + return -1;
> + idle_cpu = __select_idle_cpu(cpu, p);
> + if ((unsigned int)idle_cpu < nr_cpumask_bits)
> + return idle_cpu;
> + }
> + }
> + cpumask_andnot(cpus, cpus, sched_domain_span(sdc));
> + }
> + }
On 2022/8/23 11:45, Chen Yu wrote:
> On 2022-08-22 at 15:36:10 +0800, Yicong Yang wrote:
>> From: Barry Song <song.bao.hua@hisilicon.com>
>>
>> For platforms having clusters like Kunpeng920, CPUs within the same cluster
>> have lower latency when synchronizing and accessing shared resources like
>> cache. Thus, this patch tries to find an idle cpu within the cluster of the
>> target CPU before scanning the whole LLC to gain lower latency.
>>
>> Testing has been done on Kunpeng920 by pinning tasks to one numa and two
>> numa. On Kunpeng920, Each numa has 8 clusters and each cluster has 4 CPUs.
>>
>> With this patch, We noticed enhancement on tbench within one numa or cross
>> two numa.
>>
>> On numa 0:
>> 6.0-rc1 patched
>> Hmean 1 351.20 ( 0.00%) 396.45 * 12.88%*
>> Hmean 2 700.43 ( 0.00%) 793.76 * 13.32%*
>> Hmean 4 1404.42 ( 0.00%) 1583.62 * 12.76%*
>> Hmean 8 2833.31 ( 0.00%) 3147.85 * 11.10%*
>> Hmean 16 5501.90 ( 0.00%) 6089.89 * 10.69%*
>> Hmean 32 10428.59 ( 0.00%) 10619.63 * 1.83%*
>> Hmean 64 8223.39 ( 0.00%) 8306.93 * 1.02%*
>> Hmean 128 7042.88 ( 0.00%) 7068.03 * 0.36%*
>>
>> On numa 0-1:
>> 6.0-rc1 patched
>> Hmean 1 363.06 ( 0.00%) 397.13 * 9.38%*
>> Hmean 2 721.68 ( 0.00%) 789.84 * 9.44%*
>> Hmean 4 1435.15 ( 0.00%) 1566.01 * 9.12%*
>> Hmean 8 2776.17 ( 0.00%) 3007.05 * 8.32%*
>> Hmean 16 5471.71 ( 0.00%) 6103.91 * 11.55%*
>> Hmean 32 10164.98 ( 0.00%) 11531.81 * 13.45%*
>> Hmean 64 17143.28 ( 0.00%) 20078.68 * 17.12%*
>> Hmean 128 14552.70 ( 0.00%) 15156.41 * 4.15%*
>> Hmean 256 12827.37 ( 0.00%) 13326.86 * 3.89%*
>>
>> Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so the SMT branch
>> in the code has not been tested but it supposed to work.
>>
>> Suggested-by: Peter Zijlstra <peterz@infradead.org>
>> [https://lore.kernel.org/lkml/Ytfjs+m1kUs0ScSn@worktop.programming.kicks-ass.net]
>> Tested-by: Yicong Yang <yangyicong@hisilicon.com>
>> Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
>> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
>> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
>> ---
>> kernel/sched/fair.c | 30 +++++++++++++++++++++++++++---
>> kernel/sched/sched.h | 2 ++
>> kernel/sched/topology.c | 10 ++++++++++
>> 3 files changed, 39 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 914096c5b1ae..6fa77610d0f5 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -6437,6 +6437,30 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
>> }
>> }
>>
>> + if (static_branch_unlikely(&sched_cluster_active)) {
>> + struct sched_domain *sdc = rcu_dereference(per_cpu(sd_cluster, target));
>> +
>> + if (sdc) {
>> + for_each_cpu_wrap(cpu, sched_domain_span(sdc), target + 1) {
> Looks good to me. One minor question, why don't we use
> cpumask_and(cpus, sched_domain_span(sdc), cpus);
>> + if (!cpumask_test_cpu(cpu, cpus))
>> + continue;
> so above check can be removed in each loop?
Since we'll need to recalculate the mask of rest CPUs to test in the LLC after scanning the cluster CPUs.
> Besides may I know what version this patch
> is based on? since I failed to apply the patch on v6.0-rc2. Other than that:
>
It's on 6.0-rc1 when sent but can be cleanly rebased on rc2:
yangyicong@ubuntu:~/mainline_linux/linux_sub_workspace$ git log --oneline -3
0079c27ba265 (HEAD -> topost-cls-v7, topost-cls-v6) sched/fair: Scan cluster before scanning LLC in wake-up path
1ecb9e322bd7 sched: Add per_cpu cluster domain info and cpus_share_lowest_cache API
1c23f9e627a7 (tag: v6.0-rc2, origin/master, origin/HEAD, master) Linux 6.0-rc2
So I'm not sure where's the problem...
> Reviewed-by: Chen Yu <yu.c.chen@intel.com>
>
Thanks!
> thanks,
> Chenyu
>> +
>> + if (has_idle_core) {
>> + i = select_idle_core(p, cpu, cpus, &idle_cpu);
>> + if ((unsigned int)i < nr_cpumask_bits)
>> + return i;
>> + } else {
>> + if (--nr <= 0)
>> + return -1;
>> + idle_cpu = __select_idle_cpu(cpu, p);
>> + if ((unsigned int)idle_cpu < nr_cpumask_bits)
>> + return idle_cpu;
>> + }
>> + }
>> + cpumask_andnot(cpus, cpus, sched_domain_span(sdc));
>> + }
>> + }
> .
>
On 2022-08-23 at 15:48:00 +0800, Yicong Yang wrote:
> On 2022/8/23 11:45, Chen Yu wrote:
> > On 2022-08-22 at 15:36:10 +0800, Yicong Yang wrote:
> >> From: Barry Song <song.bao.hua@hisilicon.com>
> >>
> >> For platforms having clusters like Kunpeng920, CPUs within the same cluster
> >> have lower latency when synchronizing and accessing shared resources like
> >> cache. Thus, this patch tries to find an idle cpu within the cluster of the
> >> target CPU before scanning the whole LLC to gain lower latency.
> >>
> >> Testing has been done on Kunpeng920 by pinning tasks to one numa and two
> >> numa. On Kunpeng920, Each numa has 8 clusters and each cluster has 4 CPUs.
> >>
> >> With this patch, We noticed enhancement on tbench within one numa or cross
> >> two numa.
> >>
> >> On numa 0:
> >> 6.0-rc1 patched
> >> Hmean 1 351.20 ( 0.00%) 396.45 * 12.88%*
> >> Hmean 2 700.43 ( 0.00%) 793.76 * 13.32%*
> >> Hmean 4 1404.42 ( 0.00%) 1583.62 * 12.76%*
> >> Hmean 8 2833.31 ( 0.00%) 3147.85 * 11.10%*
> >> Hmean 16 5501.90 ( 0.00%) 6089.89 * 10.69%*
> >> Hmean 32 10428.59 ( 0.00%) 10619.63 * 1.83%*
> >> Hmean 64 8223.39 ( 0.00%) 8306.93 * 1.02%*
> >> Hmean 128 7042.88 ( 0.00%) 7068.03 * 0.36%*
> >>
> >> On numa 0-1:
> >> 6.0-rc1 patched
> >> Hmean 1 363.06 ( 0.00%) 397.13 * 9.38%*
> >> Hmean 2 721.68 ( 0.00%) 789.84 * 9.44%*
> >> Hmean 4 1435.15 ( 0.00%) 1566.01 * 9.12%*
> >> Hmean 8 2776.17 ( 0.00%) 3007.05 * 8.32%*
> >> Hmean 16 5471.71 ( 0.00%) 6103.91 * 11.55%*
> >> Hmean 32 10164.98 ( 0.00%) 11531.81 * 13.45%*
> >> Hmean 64 17143.28 ( 0.00%) 20078.68 * 17.12%*
> >> Hmean 128 14552.70 ( 0.00%) 15156.41 * 4.15%*
> >> Hmean 256 12827.37 ( 0.00%) 13326.86 * 3.89%*
> >>
> >> Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so the SMT branch
> >> in the code has not been tested but it supposed to work.
> >>
> >> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> >> [https://lore.kernel.org/lkml/Ytfjs+m1kUs0ScSn@worktop.programming.kicks-ass.net]
> >> Tested-by: Yicong Yang <yangyicong@hisilicon.com>
> >> Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
> >> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> >> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
> >> ---
> >> kernel/sched/fair.c | 30 +++++++++++++++++++++++++++---
> >> kernel/sched/sched.h | 2 ++
> >> kernel/sched/topology.c | 10 ++++++++++
> >> 3 files changed, 39 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> >> index 914096c5b1ae..6fa77610d0f5 100644
> >> --- a/kernel/sched/fair.c
> >> +++ b/kernel/sched/fair.c
> >> @@ -6437,6 +6437,30 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
> >> }
> >> }
> >>
> >> + if (static_branch_unlikely(&sched_cluster_active)) {
> >> + struct sched_domain *sdc = rcu_dereference(per_cpu(sd_cluster, target));
> >> +
> >> + if (sdc) {
> >> + for_each_cpu_wrap(cpu, sched_domain_span(sdc), target + 1) {
> > Looks good to me. One minor question, why don't we use
> > cpumask_and(cpus, sched_domain_span(sdc), cpus);
> >> + if (!cpumask_test_cpu(cpu, cpus))
> >> + continue;
> > so above check can be removed in each loop?
>
> Since we'll need to recalculate the mask of rest CPUs to test in the LLC after scanning the cluster CPUs.
>
I was thinking of introducing a temporary variable
cpumask_and(cpus_cluster, sched_domain_span(sdc), cpus);
and iterate this cpus_cluster in the loop. But since the
cpus is reused, it is ok to be as it is.
> > Besides may I know what version this patch
> > is based on? since I failed to apply the patch on v6.0-rc2. Other than that:
> >
>
> It's on 6.0-rc1 when sent but can be cleanly rebased on rc2:
>
> yangyicong@ubuntu:~/mainline_linux/linux_sub_workspace$ git log --oneline -3
> 0079c27ba265 (HEAD -> topost-cls-v7, topost-cls-v6) sched/fair: Scan cluster before scanning LLC in wake-up path
> 1ecb9e322bd7 sched: Add per_cpu cluster domain info and cpus_share_lowest_cache API
I did not apply 1/2, and that was why it failed I think. Thanks for explaination.
Thanks,
Chenyu
> 1c23f9e627a7 (tag: v6.0-rc2, origin/master, origin/HEAD, master) Linux 6.0-rc2
>
> So I'm not sure where's the problem...
>
> > Reviewed-by: Chen Yu <yu.c.chen@intel.com>
> >
>
> Thanks!
>
> > thanks,
> > Chenyu
> >> +
> >> + if (has_idle_core) {
> >> + i = select_idle_core(p, cpu, cpus, &idle_cpu);
> >> + if ((unsigned int)i < nr_cpumask_bits)
> >> + return i;
> >> + } else {
> >> + if (--nr <= 0)
> >> + return -1;
> >> + idle_cpu = __select_idle_cpu(cpu, p);
> >> + if ((unsigned int)idle_cpu < nr_cpumask_bits)
> >> + return idle_cpu;
> >> + }
> >> + }
> >> + cpumask_andnot(cpus, cpus, sched_domain_span(sdc));
> >> + }
> >> + }
> > .
> >
© 2016 - 2026 Red Hat, Inc.