The document discusses different multi-threading models: many-to-one, one-to-one, and many-to-many. The many-to-one model maps many user threads to a single kernel thread, allowing for efficient thread management but blocking all threads during system calls. The one-to-one model maps each user thread to its own kernel thread, enabling more concurrency and parallelism across processors but requiring more kernel resources. The many-to-many model multiplexes user threads to kernel threads, allowing scheduling around blocking system calls while using kernel resources efficiently.

1. MULTI THREADING MODEL
By,
R.Annalakshmi,
20PA03,
Operating system,
1-MCA
1
11-04-2021

2. Types Multi Thread Model:
To establish relationship between user thread and kernel
thread it’s called multi threading model.
 Many-to-one model
 One-to-one model
 Many-to-many model
2
11-04-2021

3. Many-to-one model:
3
11-04-2021
• Many user level thread to one kernel
level thread.
• Thread management is done by the
thread library in user space.so,it is
efficient.
• The entire process will block if a thread
makes a blocking system call.
• Multiple threads are unable to run in
parallel of multiprocessors.
• Ex: ticket booking

4. One-to-one model:
11-04-2021 4
• Each user thread have one kernel thread.
• Provides more concurrency then the
many-to-many model by allowing
another thread to run when a thread
makes a blocking system call.
• Also multiple threads run in a parallel of
multi processor.
• Creating a user thread requires
corresponding level of kernel thread.

5. Many-to-many-model:
11-04-2021 5
• Multiplexes many user-level threads to a
smaller or equal number of kernel threads.
• The number of kernel threads may be
specific to either a particular application or
a particular machine.
• Also, when a thread performs a blocking
system call, the kernel can schedule another
thread for execution.
• Ex: network

6. 11-04-2021 6