Multithreading

We have user threads and kernel threads. We must establish a relationship between user and kernel threads. There are 3 ways to do this:

1. Many to one model:one kernel thread and several user threads.

• Thread management is done by a thread library so its easy
• Entire process will block if a thread makes a blocking call
• No multithreading

2. One to one model: pairs of user threads to kernel threads.

• Multithreading

• Must have both user and kernel thread at once. Slower performance the more threads you have

3. Many to many: all user threads and all kernel threads connect to one central location

• Almost the same # of kernel threads to # of user threads
• Multithreading
• Blocking won’t disrupt system

Hyperthreading/Simultaneous Multithreading(SMT)

Same as Multithreading but used by Intel. CPU cores matter for multithreading. A single core can have multiple threads