1 Dr. Frederica Darema Senior Science and Technology Advisor NSF Future Parallel Computing Systems – what to remember from the past RAMP Workshop FCRC 2007

2 Overview Systems Modeling and Analysis is important –Design cycle and support the runtime –measurements an important (static and runtime) –performance, dependability, reliability, power management, security, …. Multicore systems –New opportunities and something from the past –What we learned from shared memory systems of the early-mid80’s

3 Authenication / Authorization Fault Recovery Services Distributed Systems Management Distributed, Heterogeneous, Dynamic, Adaptive Computing Platforms and Networks Device Technology... CPU Technology Visualization Scalable I/O Data Management Archiving/Retrieval Services Collaboration Environments Distributed Applications Memory Technology Two Components of CSR Program: * (AES) Advanced Execution Systems * (SMA) System Modeling and Analysis Prog.Models Libraries Tools Compilers Advanced Execution Systems Parallel and Distributed Operating Systems System Modeling and Analysis

4 System Modeling and Analysis (SMA) Seeks to develop methods and tools for modeling, measuring, analyzing, evaluating, and predicting the performance and correctness of complex computing and communications systems SMA emphasizes the development of methods and tools for modeling, measuring, analyzing, evaluating, and predicting the performance and correctness of complex computing and communications systems Topics of Interest Hardware and Software modeling –methods tools and measurements, providing multimodal, hierarchical or multilevel modeling and analysis capabilities of such systems; –methods that describe components of the system, but also the system as a total, and enable assessment of the effects of individual hardware and software layers and components of these systems; –ability to describe the system in multiple levels of detail (characteristics and time-scales); –combine different methods of describing components and layers

5 System Modeling and Analysis (SMA) Topics of Interest (cont’d) Novel modeling and measurement approaches –Develop capabilities to describe, analyze and predict the behavior of the components as well as the systems; Analysis and prediction due to changes in the application, system software, hardware; multilevel approaches and multi-modal approaches Performance Frameworks –combine tools in “plug-and-play” fashion –multiple views of the system Emphasis on Multidisciplinary Research (across sub-areas of CS)

6 Multiple views of the system The applications’ view Authenication/ Authorization Dependability Services Distributed Systems Management Distributed, Heterogeneous, Dynamic, Adaptive Computing Platforms and Networks Device Technology... CPU Technology Visualization Scalable I/O Data Management Archiving/Retrieval Services Other Services... Collaboration Environments Distributed Applications Memory Technology Application Models OS Scheduler Models Architecture / Network Models Memory Models IO / File Models... Languages Libraries Tools Compilers

7 Authenication/ Authorization Dependability Services Distributed Systems Management Visualization Scalable I/O Data Management Archiving/Retrieval Services Other Services... Collaboration Environments Distributed Applications Distributed, Heterogeneous, Dynamic, Adaptive Computing Platforms and Networks Device Technology... CPU Technology Memory Technology Application Models Architecture / Network Models Memory Models OS Scheduler Models IO / File Models... Languages Libraries Tools Compilers Multiple views of the system The Operating Systems’ view

8 Dynamically Link & Execute The NGS Program developsTechnology for integrated feedback & control Runtime Compiling System (RCS) and Dynamic Application Composition Application Model Application Program Application Intermediate Representation Compiler Front-End Compiler Back-End Performance Measuremetns & Models Distributed Programming Model Application Components & Frameworks Dynamic Analysis Situation Launch Application (s) Distributed Platform Adaptable computing Systems Infrastructure Distributed Computing Resources MPPNOW SAR tac-com data base fire cntl fire cntl alg accelerator data base SP ….

9 Advanced Execution Systems (AES) (a component of the Computer Systems Research Program) (CSR Program) Seeks to create systems software to facilitate the development and runtime support of complex applications executing on large, heterogeneous high-end computing and grid platforms AES emphasizes runtime compiling systems and application composition systems interface with the underlying operating systems services and incorporating systems modeling and analysis methods and tools. Topics of Interest Novel Compiler Technology that go beyond the standard static notion of a compiler –for example by embedding a portion of the compiler in the runtime and endowing the system with resource awareness and adaptive mapping capabilities; –new compiler techniques for determining functional and data dependencies across multiple levels of memory hierarchy and across platforms; –mechanisms for matching an application’s resource needs to underlying resources when both are changing as the application executes

10 Advanced Execution Systems (AES) Topics of Interest Programming models and tools –expressing application partitioning across distributed, heterogeneous computing platforms; application-level checkpointing and recovery Application composition system (ACS) technology –constructing applications to fit the available resources and to adapt to changes in the underlying execution environment; –methods for automatically selecting application components; –creating knowledge bases for application components; interfacing with the underlying computing platform models to determine suitable application components; –and developing appropriate application component libraries and interfaces so the run-time portion of the RCS can link to such libraries.

A number of projects are developing: systems modeling methods and performance frameworks & runtime-compiler and application composition systems Projects can be found in the proceedings of the Next Generation Software (Workshop Series & PI-Meetings) I organize every year in conjunction with IPDPS

The RAMP effort is very important in enabling the modeling capabilities needed for present and future computer systems and environments Can lead to a valuable standard Performance Framework usable by the broader academic community and industry

13 With respect to the Emerging Multicore Systems: Things to remember from the past Coherent caches – issues of scalability to large numbers of processors On-chip networks: –Bus-based communication – contention - & scalability issues –Cross-bars - can have contention for 100s procs (let alone 100Ks of procs ) –Consider multistage switches –Consider combining networks Test&Set/Compare& Swap - Fetch&op (e.g Fetch&Add) for synchronization Shared data –Synchronization (place in a “fast” shared memory - cache) –Other application shared data (place in shared memory – stage in cache) –Past experiments showed that even if 99% of data are shared – accesses to the shared data were ~20% Memory wall - remains challenge; reducing latency remains challenge –Hardware – pipelining –Software – compilers/prefetching Temporary cacheable shared data (compiler enabled) Performance Tools - Parallel tracing – parallel simulations