Transcript Processes and Threads - The College of New Jersey

What is a Thread?
A thread is similar to a process, but it typically
consists of just the flow of control. Multiple
threads use the address space of a single
process.
The complete name is: Thread of Execution
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The Thread Model
(a) Three processes each with one thread
(b) One process with three threads
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The Thread Model
• Items shared by all threads in a process
• Items private to each thread
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The Thread Model
Each thread has its own stack
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Why Do We Use Threads?
•To simplify programs in which multiple activities go on at once.
•Easier to create and destroy because they have no resources
attached to them - they share common memory.
•Performance gain, when there is substantial amounts of both
computing and I/O.
A word processor with three threads
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A multithreaded Web server
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Rough outline of code for web server
(a) Dispatcher thread
(b) Worker thread
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Three ways to construct a server
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Implementing Threads in User Space
A user-level threads package
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Implementing Threads in the Kernel
A threads package managed by the kernel
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Hybrid Implementations
Multiplexing user-level threads onto kernellevel threads
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