This document discusses different threading models and examples of threading implementations in operating systems. There are three dominant threading models: many-to-one maps many user threads to one kernel thread; one-to-one maps each user thread to a kernel thread and allows more concurrency; many-to-many maps many user threads to many kernel threads but true concurrency is not gained. Windows XP uses a one-to-one model where each thread has an ID and separate stacks. Linux refers to threads as tasks and uses clone() to create child tasks that share the parent's address space.

1. MULTI THREADING
MODELS
- sk jakeer hussain

2. THREAD
1.A thread is a basic utilisation of cpu ,
actually thread is a program.
2.It shares with other threads belonging to
the same process its operating systems,such
as open files & signals

3. TYPES
here are two types of threads
.Single-threaded process
.multi-threaded process

4. hreads may be provided either at user level for USER
THREADS or by kernal for KERNAL USERS.

5. MULTITHREADING MODELS
There are three dominant models for thread
libraries.
1. many-to-one
2.one-to-one
3.many-to-many

6. MANY-TO-ONE
It maps MANY USER THREADS to ONE KERNAL
THREAD

7. ONE-TO-ONE
One-to-one model ,maps each user thread to each kernal
thread .

8. ne to one model is more concurrent than many to one ,it allows
another thread to run when a thread makes blocking call.
he only drawback is that creating a user thread requires creating
the kernal thread.
“Because creating kernal thread is burden for the application”);

9. MANY-TO-MANY

Many-to-many model is many user threads to
many (equal )kernal threads.

10. any-to-many allows developper to craete more user threads as he
wishes.
rue concurency is not gained .
(“Because kernal can schedule only one thread at a time ,one-to-
one model allows graeter concurrency “);

11. hen a thread perform blocking
system call ,the kernal can schedule
another thread for exucution.

12. OPERATING SYSTEM
EXAMPLES

WindowsXPThreads

LinuxThread

13. WINDOWS XP THREADS
Implements the one-to-one mapping, kernel-level
Each thread contains
- A thread id
- Register set
- Separate user and kernel stacks
- Private data storage area

14. The primary data structures of a thread include:
ETHREAD (executive thread block)
KTHREAD (kernel thread block)
TEB (thread environment block)

16. LINUX THREADS

Linux refers to them as tasks rather than threads

Thread creation is done through clone() system
call

clone() allows a child task to share the address
space of the parent task (process)

17. REFERENCE
 OPERATING SYSTEM
CONCEPTS STUDENTS
EDITION
-ABRAHAM SILBERSCHATZ

18. THANKYOU