Messages in this thread Patch in this message | | | From | longli@linuxonh ... | Subject | [PATCH 1/3] sched: define a function to report the number of context switches on a CPU | Date | Mon, 19 Aug 2019 23:14:27 -0700 |
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From: Long Li <longli@microsoft.com>
The number of context switches on a CPU is useful to determine how busy this CPU is on processing IRQs. Export this information so it can be used by device drivers.
Signed-off-by: Long Li <longli@microsoft.com> --- include/linux/sched.h | 1 + kernel/sched/core.c | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 9b35aff09f70..575f1ef7b159 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1500,6 +1500,7 @@ current_restore_flags(unsigned long orig_flags, unsigned long flags) extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial); extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed); +extern u64 get_cpu_rq_switches(int cpu); #ifdef CONFIG_SMP extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask); extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4a8e7207cafa..1a76f0e97c2d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1143,6 +1143,12 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) } EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); +u64 get_cpu_rq_switches(int cpu) +{ + return cpu_rq(cpu)->nr_switches; +} +EXPORT_SYMBOL_GPL(get_cpu_rq_switches); + void set_task_cpu(struct task_struct *p, unsigned int new_cpu) { #ifdef CONFIG_SCHED_DEBUG -- 2.17.1
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