計算機知識點第五講線程

第五講線程Operating

System

ConceptsOverview

簡介Multithreading

Models

多線程模型

Threading

Issues

多線程要考慮的一些問題

PthreadsSolaris

2

ThreadsWindows

2000

ThreadsLinux

ThreadsJava

ThreadsSingle

and

Multithreaded

Processes單線程和多線程進程Operating

System

ConceptsBenefits好處Operating

System

ConceptsResponsiveness響應(yīng)時間Resource

Sharing資源共享

Economy經(jīng)濟Utilization

of

MP

Architectures利用多處理機結(jié)構(gòu)User

Threads用戶線程Operating

System

ConceptsThread

management

done

by

user-level

threads

library使用用戶級的線程庫完成線程的管理Examples

舉例POSIX

PthreadsMach

C-threadsSolaris

threadsKernel

Threads內(nèi)核線程Operating

System

ConceptsSupported

by

the

Kernel直接由內(nèi)核支持

Examples舉例-

Windows

95/98/NT/2000SolarisTru64

UNIXBeOSLinuxMultithreading

Models多線程模型Operating

System

ConceptsMany-to-One多對一One-to-One一對一Many-to-Many多對多Many-to-One多對一Operating

System

ConceptsMany

user-level

threads

mapped

to

single

kernel

thread.

多個用戶級線程映射到單個內(nèi)核線程。Used

on

systems

that

do

not

support

kernel

threads.

用于不支持內(nèi)核線程的系統(tǒng)上。Many-to-One

Model多對一的模型Operating

System

ConceptsOne-to-One一對一的模型Operating

System

ConceptsEach

user-level

thread

maps

to

kernel

thread.每一個用戶級的線程都映射到一個內(nèi)核的線程上。Examples-

Windows

95/98/NT/2000-

OS/2One-to-one

ModelOperating

System

ConceptsMany-to-Many

Model多對多的模型Operating

System

ConceptsAllows

many

user

level

threads

to

be

mapped

to

many

kernelthreads.容許多個用戶級的線程映射到多個內(nèi)核的線程上。Allows

the operating

system

to

create

a

sufficient

number

ofkernel

threads.

容許操作系統(tǒng)創(chuàng)建足夠多的內(nèi)核線程。

Solaris

2Windows

NT/2000

with

the

ThreadFiber

packageMany-to-Many

ModelOperating

System

ConceptsThreading

Issues多線程要考慮的一些問題Operating

System

ConceptsSemantics

of

fork()

and

exec()system

calls.fork()

和exec()

系統(tǒng)調(diào)用的語義Thread

cancellation.線程的取消Signal

handling

信號的處理Thread

pools

線程池Thread

specific

data

線程的私有數(shù)據(jù)PthreadsOperating

System

Conceptsa

POSIX

standard

(IEEE

1003.1c)API

for

thread

creation

andsynchronization.IEEE為UNIX標準化定義的一個標準。線程創(chuàng)建和同步的應(yīng)用編程的界面。API

specifies

behavior

of

the

thread

library,implementation

isup

to

development

of

the

library.該標準中的API定義了線程庫的行為，實現(xiàn)取決于線程庫的開發(fā)。Common

in

UNIX

operating

systems.UNIX操作系統(tǒng)中大都實現(xiàn)了該標準。Solaris

2

ThreadsOperating

System

ConceptsSolaris

ProcessOperating

System

ConceptsWindows

2000

ThreadsOperating

System

ConceptsImplements

the

one-to-one

mapping.Each

thread

containsa

thread

idregister

setseparate

user

and

kernel

stacksprivate

data

storage

areaLinux

ThreadsOperating

System

ConceptsLinux

refers

to

them

as

tasks

rather

than

threads.Linux中通常不叫線程，而是叫任務(wù)。Thread

creation

is

done

through

clone()system

call.線程的創(chuàng)建通過clone()系統(tǒng)調(diào)用實現(xiàn)。Clone()allows

a

child

task

to

share

the

address

space

of

theparent

task

(process)

Clone()容許子任務(wù)共享父進程的地址空間。Java

ThreadsOperating

System

ConceptsJava

threads

may

be

created

by:JAVA的線程可以按以下方法來創(chuàng)建：Extending

Thread

class

擴展線程類Implementing