Frontiers in Computer Architecture, May 3, 2005
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Architecture can mean two things
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* HW/SW interface -- classical definition of architecture
* Microarchitecture -- pipelining, branch prediction, caches, ...

Design goals for architectures
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* Performance
* Low Power
* Low Cost
* Easy to program
* Compatibility and longetivity
* Security and Reliability

Trends
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* Power consumption is now a first-order constraint
   - on desktops
   - definitely for mobile computing -- Laptops, PDAs, smart watches
* We are reaching limits of instruction-level parallelism
* Increasing use of virtual machines (Java, .NET, DX9 shaders)
  [aka 'managed code']
    - the most important interfaces is the bytecode, not the HW arch
    - frequent use of dynamic memory allocation
    - reasons: 

Trends
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* Specialization
    . on a chip - TCP/IP offload, etc.
    . different markets
    . Examples: server (Azul, Niagara); desktop; ultra-mobile; cellphone;
		game console/graphics; ...
* Parallelism, even on chip
    . Why:
       . only route to peak performance
       . better power efficiency
       . lower cost (via better yield using floorsweeping)
    . Leads to:
       . change in programming model
       . focus on interconnect and memory system, not core
       . user-level architecture changes to support communication and
         synchronization
* Architectural support for JIT/managed code
    . garbage collection
    . multithreading
    . secure code
    . etc.

* Power efficiency
    . this is highly microarchitectural
    . device properties; voltages; transistor sizes; pipeline depths; etc.
    . clock gating, etc.
    
* Dealing with device unreliability
* Dealing with device variability

AS AN ARCHITECT
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* System layers are breaking down:
  . Learn more about power
  . Learn more about applications (for parallelism)
  . Learn more about parallelism primitives

AS A PROGRAMMER
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* Learn more about parallelism
* Learn more about managed code