Windows 2000 and Solaris: Threads and SMP Management Submitted by: Rahul Bhuman

1. Windows 2000 and Solaris: Threads and SMP Management Submitted by: Rahul Bhuman

2. Solaris Processes • Process is an abstraction that contains the environment for a user program • Each process has a context and various items of state information that define the execution environment of the process • A process’s context is further divided into a hardware and software context. • Process contain one or more threads • Kernel maintains a system wide process table, where by each process is uniquely identified by a positive integer called the process identification number.

3. Hardware context (registers, stack) Scheduling class and priority Kernel process table CPU(s) Process lineage (parents, children) Signals, handlers, disposition Memory Process Address space I/O Process state Open files Session information (control terminal, job control state) Process ID (PID) Process group ID Parent process ID Credentials (UID, GID) The basic process environment, minus the thread abstractions below.

4. Windows 2000 Process • At the highest level of abstraction, windows 2000 process comprises the following: • A private virtual address space • An executable program • A list of open handles to various system resources that are accessible to all threads in the process. • A security context called an access token. • A unique identifier called a process ID • At least one thread of execution.

5. Structure of Executive Block

6. Kennel Process Block

7. Process Environment Block

8. Solaris Threads • User-Level Threads (ULTs) • Implemented through a threads library in the address space of a process • Invisible to the OS • Lightweight processes (LWPs) • A mapping between ULTs and kernel threads • Each LWP supports one or more ULTs and maps to one kernel thread • Scheduled by the kernel independently • May execute in parallel on multiprocessors • Kernel threads • Fundamental entities that can be scheduled and dispatched to run on one of the system processors

9. Unbound user threads are scheduled within the threads library, where the selected user thread is linked to an available LWP. Software context: open file, credential, address space, process group, session control,… Software context: open file, credential, address space, process group, session control,… User thread User thread User thread User thread User thread User thread Process Process LWP| Machine state LWP| Machine state LWP| Machine state LWP| Machine state CPU Kthread Kthread Kthread Kthread Solaris Multithreaded process model

10. Windows 2000 Threads • A thread is the entity within a process that Windows 2000 schedules for execution. • Thread Includes: • The contents of a set of CPU registers representing the state of the processor • Two stacks • A private storage area called thread-local storage (TLS) • A unique identifier called a thread ID • Threads sometimes have their own security context

11. Structure of ETHREAD block

12. Kernel Thread Block Thread Environment Block (TEB)

13. Solaris Thread States

14. Windows 2000 Thread States

15. Class Priority Range Global Priority Range Scheduling Class 0 - 59 000 – 059 Time Share and Interactive 0 – 39 060 – 099 System 0 – 9 100 – 109 Interrupt Threads if the Real time class is not loaded 0 – 59 100 – 159 Real Time 0 – 9 160 – 169 Interrupt threads if the RT class is loaded Solaris Thread Scheduling 10 59 interrupt ints 169 User Range priority Real Time 1 0 +60 User Range priority interactive System -60 +60 User Range priority Time Share 0 -60

16. Windows 2000 Thread Scheduling

17. Windows 2000 Symmetric Multiprocessing

18. Windows 2000 Symmetric Multiprocessing • Windows 2000 is a symmetric multiprocessing (SMP) operating system. There is no master processor. • Windows 2000 incorporates several features that are crucial to its success as a multiprocessor operating system: • The ability to run operating system code on any available processor and on multiple processors at the same time • Multiple threads of execution within a single process, each of which can execute simultaneously on different processors • Fine-grained synchronization within the kernel as well as within device drivers and server processes, which allows more components to run concurrently on multiple processors

19. Solaris Symmetric Multiprocessing A Single Multiprocessor system. Shared memory, symmetric system with uniform memory and I/O access. Single kernel image shared by all processes – single address space view. 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 A system interconnect, either bus or cross – bar design. Cache – coherent protocol for data transfers to/from memory, processors, and I/O. Very high, sustainable bandwidth with uniform access times (latency) 1 is CPU (s) 2 is Memory 3 is I/O

20. Solaris Symmetric Multiprocessing • Solaris supports shared memory architecture, which implements a single kernel shared by all the processors and single uniform memory address space. • Symmetric Multiprocessor describes a system in which a peer-to-peer relationship exists among all the processors (CPUs) on the system • All processors are equal

21. References • Solaris Internals – Core Kernel Architecture • Jim Mauro and Richard McDougall • Inside Microsoft Windows 2000: Third Edition • David A. Solomon and Mark E.Russinovich • Operating Systems: Internals and Design Principles • William Stallings