On Wed, Dec 14, 2005 at 08:32:37 +0300, MHD.Tayseer Alquoatli wrote: > > It depends on what you call a "user-level" thread. Threads created with > > pthreads *ARE* scheduled by kernel. > > i understand from your sentence that pthreads are a user-level threads but > the kernel is aware of them and do the scheduling for them. is this means > that calling a blocking operation from one pthread will NOT block the whole > process ? so what do i miss ? does pthreads create threads using clone > syscalls ? or is there is a second definition of user-level threads ? > correct me please User-level threads is usually used to mean "the user-space library creates some kind of threads inside a single process". Ie. the threads NOT created with clone(). In this sense, pthreads do NOT create user-level threads. They create kernel-level threads. Which are not to be confused with kernel threads. Linux phtreads, both old-style and new-style (using ntpl available in 2.6 kernels) use clone to create the threads. > kernel-level threads and kernel threads are two vastly different things. > > kernel-level thread (usually) means: A thread of a user space > > application, that is a schedulable entity. > > kernel thread means: A schedulable entity that runs kernel space code > > and has no associated user space. > > > thank you for clarifying this point. i was unaware of the difference Well, on a kernel-related list, you need to make a distinction between threads running userspace code where kernel takes care of the threading (kernel-level threads) and threads running kernel code (kernel threads). -- Jan 'Bulb' Hudec <bulb@xxxxxx>
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