How can I see which CPU core a thread is running in?

linux linux-kernel scheduled-tasks scheduling scheduler
flypen picture flypen · Nov 7, 2011 · Viewed 92.7k times · Source

In Linux, supposing a thread's pid is [pid], from the directory /proc/[pid] we can get many useful information. For example, these proc files, /proc/[pid]/status,/proc/[pid]/stat and /proc/[pid]/schedstat are all useful. But how can I get the CPU core number that a thread is running in? If a thread is in sleep state, how can I know which core it will run after it is scheduled again?

BTW, is there a way to dump the process(thread) list of running and sleeping tasks for each CPU core?

Answer

maltanar picture maltanar · Jul 12, 2012

The "top" command may help towards this, it does not have CPU-grouped list of threads but rather you can see the list of threads (probably for a single process) and which CPU cores the threads are running on by

top -H -p {PROC_ID}

then pressing f to go into field selection, j to enable the CPU core column, and Enter to display.

Related questions

Why do we need a swapper task in linux?

The idle task (a.k.a. swapper task) is chosen to run when no more runnable tasks in the run queue at the point of task scheduling. But what is the usage for this so special task? Another question is …

Read More
Increasing the maximum number of TCP/IP connections in Linux

I am programming a server and it seems like my number of connections is being limited since my bandwidth isn't being saturated even when I've set the number of connections to "unlimited". How can I increase or eliminate a maximum …

Read More
What is ":-!!" in C code?

I bumped into this strange macro code in /usr/include/linux/kernel.h: /* Force a compilation error if condition is true, but also produce a result (of value 0 and type size_t), so the expression can be used e.g. …

Read More