★ Threads ￥ 斗 ★★ o Invented to support multiprogammingon processlevel o Manage OS complexity Multipleusers, progams, Io devices, etc. s Each thread dedicated to do one task 16
16 Threads Invented to support multiprogramming on process level Manage OS complexity – Multiple users, programs, I/O devices, etc. Each thread dedicated to do one task
★ Thread ￥ 斗 ★★ o Sequence of executinginstructions froma progam i.e. the runningcomputation o Play analogy: one actor on stage in a play
17 Thread Sequence of executing instructions from a program – i.e. the running computation Play analogy: one actor on stage in a play
★ Threads ￥ 斗 ★★ o Processes decompose mix of activities into several parallel tasks(columns o Each job can work independently of others job1 Joba job Thread 1 Thread 2 Thread 3
18 Threads Processes decompose mix of activities into several parallel tasks (columns) Each job can work independently of others job1 job2 job3 Thread 1 Thread 2 Thread 3
★ The Thread model ￥ 斗 ★★ Proc 1 proc 2 proc 3 Process User space Thread Thread Kernel Kernel Kernel space 3 processes each with 1 thread 1 process with 3 threads
19 The Thread Model 3 processes each with 1 thread 1 process with 3 threads Kernel Thread Proc 1 Proc 2 Proc 3 User space Kernel space Kernel Thread Process
★ The thread model ￥ 斗 ★★ o Some items shared by all threads in a process o Some items private to each thread
20 The Thread Model Some items shared by all threads in a process Some items private to each thread