I want to print CPU number on which the current process or function is executing similar to ftrace like this:
我想打印当前进程或函数执行的CPU编号，类似于ftrace:
TASK-PID CPU# TIMESTAMP FUNCTION
| | | | |
<idle>-0 [002] 23636.756054: ttwu_do_activate.constprop.89 <-try_to_wake_up
<idle>-0 [002] 23636.756054: activate_task <-ttwu_do_activate.constprop.89
<idle>-0 [002] 23636.756055: enqueue_task <-activate_task
How do I get that value? I suppose its there in some function of start_kernel function. Can we print its value? I am using linux-4.1 kernel.
如何得到这个值?假设它在start_kernel函数的某个函数中。我们可以打印它的值吗?我正在使用linux-4.1内核。
1 个解决方案
#1
3
For printing current cpu in kernel, the cpu field of task_struct can be used. Note that the kernel configuration CONFIG_THREAD_INFO_IN_TASK should be enabled. This will work for 4.9 kernel.
对于在内核中打印当前cpu，可以使用task_struct的cpu字段。注意，内核配置CONFIG_THREAD_INFO_IN_TASK应该启用。这将适用于4.9内核。
printk("My current cpu is %d\n", current->cpu);
smp_processor_id() also can be used if cpu field is not available.
如果cpu字段不可用，也可以使用smp_processor_id()。
#1
3
For printing current cpu in kernel, the cpu field of task_struct can be used. Note that the kernel configuration CONFIG_THREAD_INFO_IN_TASK should be enabled. This will work for 4.9 kernel.
对于在内核中打印当前cpu，可以使用task_struct的cpu字段。注意，内核配置CONFIG_THREAD_INFO_IN_TASK应该启用。这将适用于4.9内核。
printk("My current cpu is %d\n", current->cpu);
smp_processor_id() also can be used if cpu field is not available.
如果cpu字段不可用，也可以使用smp_processor_id()。