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Technical Report no. 2002-02 NOBLE A Non-Blocking Inter-Process Communication Library 1

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TechnicalReportno.2002-02

NOBLE:ANon-BlockingInter-ProcessCommunicationLibrary1

HåkanSundellPhilippasTsigas

DepartmentofComputingScience

ChalmersUniversityofTechnologyandGöteborgUniversity

SE-41296Göteborg,Sweden

Göteborg,2002

1PerformedwithinthenetworkforReal-TimeresearchandgraduateEducationinSweden(ARTES),supportedbytheSwedishFoun-dationforStrategicResearch(SSF)

TechnicalReportinComputingScienceat

ChalmersUniversityofTechnologyandGöteborgUniversity

TechnicalReportno.2002-02

ISSN:1650-3023

DepartmentofComputingScience

ChalmersUniversityofTechnologyandGöteborgUniversity

SE-41296Göteborg,Sweden

Göteborg,Sweden,2002Abstract

Manyapplicationsonsharedmemorymulti-processor

machinescanbenefitfromtheexploitationofparallelism

thatnon-blockingsynchronizationoffers.Inthispaper,we

introducealibrarysupportformulti-processnon-blocking

synchronizationcalledNOBLE.NOBLEprovidesaninter-

processcommunicationinterfacethatallowstheusertose-

lectsynchronizationmethodstransparentlytotheonethat

suitsbestforthecurrentapplication.Thelibraryprovidesa

collectionofthemostcommonlyuseddatatypesandproto-

colsinaform,whichallowsthemtobeusedbynon-experts.

Wedescribethefunctionalityandtheimplementationof

thelibraryfunctionsandillustratethelibraryprogramming

stylewithexampleprograms.Theexamplesshowthatus-

ingthelibrarycanconsiderablyreducetheruntimeondis-

tributedsharedmemorymachines.

1Introduction

Softwareimplementationsofsynchronizationconstructs

areusuallyincludedinsystemlibraries.Thedesignofa

goodsynchronizationlibrarycanbechallengingandmany

efficientimplementationsforthebasicsynchronizationcon-

structs(locks,barriersandsemaphores)havebeenproposed

intheliterature.Manysuchimplementationshavebeen

designedwiththeaimtolowerthecontentionwhenthe

systemisinahighcongestionsituation.Theseimple-

mentationsgivedifferentexecutiontimesunderdifferent

contentioninstances.Butstillthetimespentbythepro-

cessesonthesynchronizationcanformasubstantialpartof

theprogramexecutiontime[KarLMS91,MelS91,MicS98,

NikP99,ZahLE91].Thereasonforthisisthattypicalsyn-

chronizationisbasedonblockingthatunfortunatelyresults

inpoorperformance.Thisisbecauseblockingproduces

highlevelsofcontentiononthememoryandtheintercon-

nectionnetwork,andmoresignificantly,becauseitcauses

convoyeffects:ifoneprocessholdingalockispreempted,

otherprocessesondifferentprocessorswaitingforthelock

willnotbeabletoproceed.Researchershaveintroduced

non-blockingsynchronizationtoaddresstheaboveprob-

lems.

Therehasbeenmuchadvocacyarisingfromthethe-

orycommunityfortheuseofnon-blockingsynchroniza-

tionprimitivesratherthanblockingones,inthedesignof

inter-processcommunicationmechanismsforparalleland

highperformancecomputing.Thisadvocacyisintuitive

andmanyresearchershaveformorethantwodecadesde-

velopedefficientnon-blockingimplementationsforseveral

shareddataobjects.Despitethis,thescientificdiscover-

iesonnon-blockingsynchronizationhavenothavemigrated

muchintopractice,eventhoughsynchronizationisstillthebottleneckinmanyapplications.Thelackofastandardli-

braryofnon-blockingsynchronizationofshareddataob-

jectscommonlyusedinparallelapplicationshasplayeda

significantroleforthisslowmigration.

NOBLEoffersalibrarysupportformulti-processnon-

blockingsynchronizationforsharedmemorysystems.NO-

BLEhasbeendesignedinorder:I)toprovideacollection

ofshareddataobjectsinaformwhichallowsthemtobe

usedbynon-experts,II)toofferanorthogonalsupportfor

synchronizationwheretheapplicationcanchangesynchro-

nizationimplementationswithminimalchanges,III)tobe

easytoporttodifferentmulti-processorsystems,IV)tobe

adaptablefordifferentprogramminglanguagesandV)to

containefficientknownimplementationsofitsshareddata

objects.

Therestofthepaperisorganizedasfollows.Section2

outlinesthebasicfeaturesofNOBLEandtheimplementa-

tionanddesignstepsthathavebeentakentosupportthese

features.Section3illustratesbyawayofanexamplethe

useofthefeaturesofNOBLEinapracticalsetting.Section

4presentsrun-timeexperimentsusingNOBLEthatshow

theperformancebenefitsofnon-blockingsynchronization.

Finally,Section5concludesthispaper.

2DesignandFeaturesofNOBLE

WhendesigningNOBLEweidentifiedanumberofchar-

acteristicsthathadtobecoveredfromourdesigninorder

tomakeNOBLEeasytouseandusablebyawiderangeof

practitioners.WedesignedNOBLEtohavethefollowing

features:

Usability-Scope-NOBLEprovidesacollectionof

fundamentalshareddataobjectsthatarewidelyused

inparallelandreal-timeapplications.

Easytouse-NOBLEprovidesasimpleinterfacethat

allowstheusertousethenon-blockingimplementa-

tionsoftheshareddataobjectsthesamewaytheuser

wouldhaveusedlock-basedones.

EasytoAdapt-Noneedforchangesattheapplication

levelarerequiredbyNOBLEanddifferentimplemen-

tationsofthesameshareddataobjectsaresupported

viaauniforminterface.

Efficient-Userswillhavetoexperiencemajorim-

合集下载

确定考题ENG

确定考题ENG

翻译：

The effort is necessitated by the potential complexity of those systems,which may contain

millions of lines of code.

对于可能包含数百万行代码的系统所具有的潜在的复杂性来说这一努力是有必要的。

The discipline of software engineering includes konwledge,tools,and methods for software

requirements,software design,software construction,software testing,and software maintenance

tasks.

软件工程学科包括关于软件需求、软件设计、软件架构、软件测试和软件维护任务得知识、工具和方法。

A 2003 study found that some spurious computer crashes and general reliability issues, ranging

from screen image distortions to I/O read/write errors, can be attributed not to software or

peripheral hardware but to aging capacitors on PC motherboards.2003年的一个研究发现，一些伪劣的计算机损毁和常规可靠性的问题，从屏幕图像失真到输入/输出读写错误，并不是由于软件或外围硬件引起的，而是由于PC机主板上老化的电容器造成的。

阅读：

Unit6

_F_ 1. A distributed database is a database stored in multiple computers located in the same

国防科技大学 国防科技大 2002年操作系统 考研真题及答案解析

国防科技大学 国防科技大 2002年操作系统 考研真题及答案解析

国防科技大学研究生院2002年硕士生入学考试试题

考试科目：519-操作系统

题单号：50619 （可不抄题）

考生注意：1、考生注答案必须写在我校统一配发的专用答题纸上！

2、统考生做：一、二、三、四、五；

3、单独考生做一、二、三、六、七；

一、（60分）回答如下问题

1、（6分）将“I/O为主”的进程定义为：当此类进程单独运行时，用于I/O处理的时间远远多于处

理机的处理时间；将“计算为主”的进程定义为：当此类进程单独运行时，处理机的处理时间远远

多于I/O处理的时间。若系统中运行的主要是这两类进程，采用什么样的调度算法更有利于提高系

统资源的利用率？为什么？

2、（8分）请给出PCB（进程控制块）的主要内容。描述当进程发生下述状态转换时，就绪→运行，

运行→阻塞，操作系统需要使用/修改PCB中的哪些内容。

3、（5分）请问，在一个进程中使用多线程有何优点？

4、（5分）设系统中有下述解决死锁的办法：

. 银行家算法

. 检测死锁，中止死锁状态的进程、释放该进程占有的资源

. 资源预分配

请问哪种方法允许最大的并发性，也即，哪种办法允许更多的进程无等待的向前推进？请按“并发

性”从大到小对上述三种办法排序。

5、（8分）请描述页式虚存管理系统中叶表项的主要内容。请简要描述“缺页中断”的处理过程，

并结合该过程，说明其中使用/修改了页表项的哪些内容。

6、（6分）简述OS对文件读/写的系统调用所完成的工作。

7、（6分）简述以程序中断I/O方式，从外设读入一包含N个字节的数据块的过程。

8、（8分）若允许文件能分别在开始、中间、末尾增长，试讨论在顺序式、链接式以及索引式文件

物理组织下的开销。

9．（8分）（1）给出无忙等待的P、V操作的定义

（１）考虑下述P、V操作的定义

P（s）：

if s.value>0

Then

s.value=s.value-1

else begin

place this puocess in s.queue;

ASTM A471-02

ASTM A471-02

Designation:A471–02

StandardSpecificationfor

Vacuum-TreatedAlloySteelForgingsforTurbineRotor

DisksandWheels1

ThisstandardisissuedunderthefixeddesignationA471;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.

1.Scope*

1.1Thisspecificationcoversvacuum-treatedalloysteel

forgingsintendedforuseasturbinerotordisksandwheels.

1.2Thevaluesstatedininch-poundunitsaretoberegarded

asthestandard.

2.ReferencedDocuments

2.1ASTMStandards:

A275/A275MTestMethodforMagneticParticleExami-

nationofSteelForgings2

A370TestMethodsandDefinitionsforMechanicalTesting

ofSteelProducts3

A388/A388MPracticeforUltrasonicExaminationof

HeavySteelForgings2

2002 disney annual report

2002 disney annual report

The Walt Disney Company and Subsidiaries

M A NAGEMENT’S DISCUSSION AND A NA LYSIS OF F I NANCIAL CONDITION AND RESULTS OF OPERAT I O N S

C O N S O L I DATED RESULT S

A s - Rep o rted Results ofO p e rat i o n s(in millions, except per share data)200220012000

Revenues$25,329$25,172$25,325

Costs and expenses(22,924)(21,573)(21,567)

Amortization of intangible assets(21)(767)(1,233)

Gain on sale of businesses3422489

Net interest expense and other(453)(417)(497)

Equity in the income of investees225300208

Restructuring and impairment charges—(1,454)(92)

Income before income taxes, minority interests and the cumulative effect of accounting changes2,1901,2832,633

Income taxes(853)(1,059)(1,606)

Minority interests(101)(104)(107)

Income before the cumulative effect of accounting changes1,236120920

Cumulative effect of accounting changes:

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