打印类似于ftrace的CPU编号 [英] Printing CPU number similar to ftrace
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问题描述
我要打印正在执行当前进程或功能的CPU编号,类似于ftrace,如下所示:
I want to print CPU number on which the current process or function is executing similar to ftrace like this:
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
我如何获得该价值?我猜想它在start_kernel
函数的某个函数中存在.我们可以打印它的值吗?我正在使用linux-4.1
内核.
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.
推荐答案
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.
printk("My current cpu is %d\n", current->cpu);
如果CPU字段不可用,也可以使用
smp_processor_id()
.
smp_processor_id()
also can be used if cpu field is not available.
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