The kernel thread powering it is lost for the durafon

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Unformatted text preview: University of Washington User-level threads: what the kernel sees address space os kernel thread CPU 34 34 25 May 2012 Processes & Threads 34 University of Washington User-level threads: the full story user-level thread library Mach, NT, Chorus, Linux, … address space os kernel thread (thread create, destroy, signal, wait, etc.) kernel threads CPU (kernel thread create, destroy, signal, wait, etc.) 35 25 May 2012 Processes & Threads 35 University of Washington User ­level threads   User ­level threads are small and fast   managed enMrely by user ­level library E.g., pthreads (libpthreads.a)   each thread is represented simply by a PC, registers, a stack, and a small thread control block (TCB)   creaMng a thread, switching between threads, and synchronizing threads are done via procedure calls   no kernel involvement is necessary!   user ­level thread operaMons can be 10 ­100x faster than kernel threads as a result   25 May 2012 Processes & Threads 36 University of Washington User ­level thread implementaFon       The OS schedules the kernel thread The kernel thread executes user code, including the thread support library and its associated thread scheduler The thread scheduler determines when a user ­level thread runs   it uses queues to keep track of what th...
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This document was uploaded on 04/04/2014.

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