1. Silberschatz, Galvin, Gagne ©2002 (with gcw mods). 5.1. Operating System
Concepts. Chapter 5: Threads. ▫ Overview. ▫ Multithreading Models.
Chapter 5: Threads
n Overview n Multithreading Models n Threading Issues n Pthreads n Solaris 2 Threads n Windows 2000 Threads n Linux Threads n Java Threads
Operating System Concepts
5.1
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Single and Multithreaded Processes
Operating System Concepts
5.2
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
1
Benefits
n Responsiveness n Resource Sharing n Economy n Utilization of MP Architectures
Operating System Concepts
5.3
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
User Threads
n Thread management done by user-level threads library n Examples
- POSIX Pthreads - Mach C-threads - Solaris threads
Operating System Concepts
5.4
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
2
Kernel Threads
n Supported by the Kernel n Examples
- Windows 95/98/NT/2000 - Solaris - Tru64 UNIX - BeOS - Linux
Operating System Concepts
5.5
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Multithreading Models
n Many-to-One n One-to-One n Many-to-Many
Operating System Concepts
5.6
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
3
Many-to-One
n Many user-level threads mapped to single kernel thread. n Used on systems that do not support kernel threads.
Operating System Concepts
5.7
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Many-to-One Model
Operating System Concepts
5.8
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
4
One-to-One
n Each user-level thread maps to kernel thread. n Examples
- Windows 95/98/NT/2000 - OS/2
Operating System Concepts
5.9
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
One-to-one Model
Operating System Concepts
5.10
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
5
Many-to-Many Model
n Allows many user level threads to be mapped to many
kernel threads. n Allows the operating system to create a sufficient number of kernel threads. n Solaris 2 n Windows NT/2000 with the ThreadFiber package
Operating System Concepts
5.11
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Many-to-Many Model
Operating System Concepts
5.12
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
6
Threading Issues
n Semantics of fork() and exec() system calls. n Thread cancellation. n Signal handling n Thread pools n Thread specific data
Operating System Concepts
5.13
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Pthreads
n a POSIX standard (IEEE 1003.1c) API for thread creation
and synchronization. n API specifies behavior of the thread library,
implementation is up to development of the library. n Common in UNIX operating systems.
Operating System Concepts
5.14
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
7
Solaris 2 Threads
Operating System Concepts
5.15
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Solaris Process
Operating System Concepts
5.16
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
8
Windows 2000 Threads
n Implements the one-to-one mapping. n Each thread contains
- a thread id - register set - separate user and kernel stacks - private data storage area
Operating System Concepts
5.17
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Linux Threads
n Linux refers to them as tasks rather than threads. n Thread creation is done through clone() system call. n Clone() allows a child task to share the address space of
the parent task (process)
Operating System Concepts
5.18
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
9
Creating thread in Windows
HANDLE CreateThread( LPSECURITY_ATTRIBUTES lpThreadAttributes, // pointer to security attributes DWORD dwStackSize, // initial thread stack size LPTHREAD_START_ROUTINE lpStartAddress, // pointer to thread function LPVOID lpParameter, // argument for new thread DWORD dwCreationFlags, // creation flags LPDWORD lpThreadId // pointer to receive thread ID );
Operating System Concepts
5.19
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
Thread creation example
Int threadNumber; DWORD id; //DWORD == unsigned long const HANDLE h = CreateThread(0, //default security 0, //default the stack size Greeter, //our function &threadNumber, //void * to arbitrary user information 0, //no flags &id);
Operating System Concepts
5.20
Silberschatz, Galvin, Gagne 2002 (with gcw mods)
10
Thread function
DWORD WINAPI Greeter(void *arg) { const int *pval = static_cast(arg); const int & val = *pval; cout
