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CMPT 886: Special Topics in Operating Systems and Computer ArchitectureDr. Alexandra FedorovaSchool of Computing ScienceSFUSYNAR Systems Networking and Architecture Group

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Meet the InstructorPh.D. in Computer Science from Harvard, 2006Dissertation on operating system design for multicore processorsConcurrently with Ph.D., an intern at Sun Labs (3 years)Third year at SFUOver 20 publications on research topics related to multicore processorsIndustrial collaborations with Oracle (Sun Microsystems), Intel, Google, Electronic Arts, STMicroelectronics

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Course TopicMulticore processorsNew type of computer architectureDominates new processor marketDesktops, servers, mobile devices, etc. Almost all new processors are multicoreMany research problems to solveHow to design software for these chips? How to design the chips themselves?How to structure hardware/software interaction? SYNAR Systems Networking and Architecture Group

TodayIntroduction to multicore processorsExamples of research problemsOverview of the course SYNAR Systems Networking and Architecture Group

Conventional vs. MulticoreCore 0

Conventional processorSingle coreOne thread at a timeCore 0Core 1Multicore processorsSeveral coresMany threads simultaneously

Core 2Core 3

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The Multicore RevolutionMost new processors are multicoreintel.com: Most new processors are multicore:2006: 75% for desktops, 85% for servers2007: 90% for desktop and mobile, 100% for serversEveryones doing itOracle (Sun Microsystems Rock), Niagara 1, Niagara 2IBM Power4, Power5, Power6, CellAMD Quad Core (Barcelona)Embedded: ARM, STMicroelectronics SYNAR Systems Networking and Architecture Group

Why Multicore?Building conventional chips no longer profitableHow do you speed up a conventional chip? Increase its clock frequencyNo longer feasible:Increasing clock speed increases power consumption out of proportionChips are too expensive to build (errors)Too expensive to operate (energy consumption) SYNAR Systems Networking and Architecture Group

Multicore is the Answer!Instead of using one large fast coreUse many smaller, simpler coresCollectively, they use less powerCollectively, they give more computing power SYNAR Systems Networking and Architecture Group

Superior Performance/WattExample:Reduce CPU clock frequency by 20%Power consumption reduces by 50%!Core 0Core 10.8x frequency0.8x frequencyPut two 0.8 frequency cores on the same chip

Get 1.6 times the computation at the same power consumption0.5x power0.5x power SYNAR Systems Networking and Architecture Group

Multicore vs. UnicoreMulticore:1.6x throughput increaseNo power consumption increaseSingle-core:Given the same power envelopePotentially 60% less throughput SYNAR Systems Networking and Architecture Group

Source: Sutter, The Free Lunch is overTransistor density still risingClock speed isntTransistors are used for parallelism: multicore processors SYNAR Systems Networking and Architecture Group

Multicore: State of AffairsMulticore processors are hereOperating systems and applications run on them unmodifiedWhy do we need to do research on them? SYNAR Systems Networking and Architecture Group

The Multicore ChallengeArchitectureWe do not yet know whats the best way to build these processorsResource sharingWe need to manage more shared resources than beforeProgrammabilityEveryone must run multithreaded applications now, and this is hard

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Example I (Architecture)Core 0Core 0Core 1Core 2Core 3Core 0Core 1Core 2Core 3Core 4Core 5Core 6Core 7??Core 2Core 3Core 4Core 5?Core 0Core 1 SYNAR Systems Networking and Architecture Group

The Multicore ChallengeArchitectureWe do not yet know whats the best way to build these processorsResource sharingWe need to manage more shared resources than beforeProgrammabilityEveryone must run multithreaded applications now, and this is hard

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Resource SharingCore 0L2 cacheL1 cacheCore 0Core 1L2 cacheL1 cacheL1 cacheCore 0Core 1L2 cacheL1 cacheL1 cacheL2 cacheL3 cache SYNAR Systems Networking and Architecture Group

The Multicore ChallengeArchitectureWe do not yet know whats the best way to build these processorsResource sharingWe need to manage more shared resources than beforeProgrammabilityEveryone must run multithreaded applications now, and this is hard

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ProgrammabilityHow do you write multithreaded code?Is it easy? In the past, writing multithreaded code is the prerogative of experienced programmersNow everyone has to do itCan we make this easier? SYNAR Systems Networking and Architecture Group

SummaryMulticore systemsThey are everywhere: servers, desktops, small devicesMust understand themPlenty of research on multicore systemsSystem software (OS, compilers, runtimes)ArchitectureAnalytical modelingApplications

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Class StructureLearn about multicore researchRead and critique papers Paper summaries, presentationsLearn how to do multicore researchDiscuss papers, think about new ideasAnalyze papersLearn how to use research tools (1 homework)Do multicore researchA research project SYNAR Systems Networking and Architecture Group

Research ProjectA unique experience: getting a project done from start to endGoal: generate a publicationPrevious years: 2-4 publications out of 4-6 projectsGives you confidence as a grad studentImproves your resumeChallenging! You will learn a lot! SYNAR Systems Networking and Architecture Group

What Is Expected from YouExpect to work hardBut youll be glad you did this laterPapers will be difficult to read at first (3-5 hours/paper)Will get easy laterReward: You will be comfortable at leading your own research in this area

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Final ProjectYou can choose from a list of existing topicsOr create your ownSome projects are very well specified (like an undergraduate course project)Others are more open-ended (hint: an opportunity to be creative)We have systems and tools youll need for the project

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Final Project (cont.)Commit to a project proposal in early FebruaryComplete the project by mid-AprilYou have only 2.5monthsHave to work hard!Expect to dedicate 30 hrs/week SYNAR Systems Networking and Architecture Group

Will I Succeed in this Course?You have to work independently!You have to be entrepreneurial!Take full responsibility for your projectI will help, but I cannot do it for youI do not have all the answersMaybe there is no answer the goal is to learnI will stress methodologyYou will succeed, if you are prepared to work hardWhat you can or cannot do now does not matter what matters is how well you learnThe course is designed to train you SYNAR Systems Networking and Architecture Group

Course Web SiteSyllabusWikiMulticore portalTechnical documentation SYNAR Systems Networking and Architecture Group

AdministriviaThursday LabSign up for paper presentationsMeet graduate students SYNAR Systems Networking and Architecture Group