october 2007susan eggers: sosp women's workshop 1 your speaker in a nutshell ba in economics...

October 2007 Susan Eggers: SOSP Women's Workshop

1

Your Speaker in a Nutshell

BA in Economics 1965PhD University of CA, Berkeley 1989

Technical skills and innovations that married architecture & compilers.

Mostly collaborations.Pushed for quality over quantity, technology transfer &

impactI have always loved my job.

Thesis: better understanding of sharing behaviorMVP: Simultaneous MultithreadingCurrent work: a new life for dataflow machines

Transitioning to retirement (golf, gardening & landscaping, food snob).


2

Challenge in Computer Architecture

There’s one biggie: programs run faster


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The Underlying Cause


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How Architects are Addressing the Challenge

Some things we have some idea how to do:• More aggressive speculation (threads, memory,

value)• More aggressive recovery mechanisms

(transactional memory)• Lighter-weight locking mechanisms• Exploiting super-fine-grain parallelism with

dataflow execution• Adding a few more processors• The engineering: building hardware for sharing

and concurrency


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Some things we have not a clue about:• Writing parallel codes for 100s or 1000s of

processors• Discovering other than embarrassingly parallel, coarse-grain parallelism

• Determining the best programming model for writing parallel codes

• Should the programmer detect parallelism or should the compiler do it automatically?

• Devising language constructs to express parallelism

• Exploiting the concurrency once we’ve discovered it

• Avoiding race conditions, deadlock, livelock• Doing all this in a way that is simple and intuitive for the programmer


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Some things we have not a clue about:

• Executing with 100s or 1000s of processors

• Making good trade-offs between load balancing & locality

• Recovering from failing processors (RAID issues)


7

Rules of Thumb for Picking New Research Projects

How to develop a nose for good research ideas.

What in the underlying technology or application space has changed?• How has it changed?

How does that affect my area of interest?• In what areas can I no longer do business as usual?• Where are the new performance bottlenecks?• What opportunities does the change bring?• What technology or techniques that went out of style can be

resurrected?

Caveat: technology trends don’t always turn out the way you expect• CCDs failed in computers; Prologue failed• Are supercomputers failing?• Will quantum and DNA computing succeed?


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Examples of OS Research that are Driven by Computer Architecture

The operating system:

• How do you design an OS for 1000s of processors?

• How do current OSs hinder scalability? Where are the bottlenecks? Where are the centralized software structures?

• Do you start from scratch?

• Great opportunity to design free of tradition & an industry standard

• What should be the key design criteria?

• Do you use virtual machines to execute programs on small clusters of processors and then build a programming environment that hides that?


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Transactional memory:

• How should programs written with transactions interface with the OS?

• What does rollback mean over a network?

Security:

• What if everyone is a parallel programmer?

• latent concurrency bugs, deadlock, livelock

• What are the implications for security?


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Fine-grain threads:

• The OS has to support more than pthreads.

• How fine-grain can/should they be?

• And stepping back, what is a thread? Can it be data centric?

Virtual machine support in hardware:

• What if virtual machines were very light-weight?

• What might you use them for and how?

• Can a virtual machine replace a process? a protection domain?


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Examples of OS Research that are Driven by Something Else

New applications:• How will Google’s needs change the OS?• How should the OS manage fast I/O between CPUs (10Gb)?

• How can the OS make up for its absence?

Phase-change memory (fast, non-volatile, but high power)How would you build a file system if you didn’t need disks?

Third-world computing:• Low-cost, low-power, multi-lingual, multiple education

levels, different apps• What does the OS look like?

More powerful processor, same number of pins?• How do you feed it?

october 2007susan eggers: sosp women's workshop 1 your speaker in a nutshell ba in economics...

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