Linux Pthreads User level or kernel level [duplicate]

Question

Possible Duplicate:
how are pthreads on linux seen by scheduler

Are Linux pthreads user level threads or Kernel level threads ?

Answer 1

The Linux kernel schedules threads rather than processes. As far as the scheduler is concerned, processes are now an artificial construct mostly for userland purposes.

When you create a process, it is a single thread where the thread ID (the kernel actually refers to this as a PID but that might be confusing so I'll refer to it as a TID here) and thread group ID (TGID) are identical.

If a thread creates a new thread (rather than a new process), it inherits the TGID from the creator, but gets a new TID.

In other words, the thread group can be considered the process, but the scheduler doesn't care - it works on individual threads.

So, in answer to your specific question, they're kernel-level threads.