German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 1 EPOS and Myrinet: Effective Communication Support for Parallel Applications Running on Clusters of Workstations Antônio Augusto Fröhlich Gilles Pokam Tientcheu Wolfgang Schöder-Preikschat May 2000

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 2 Outline Introduction Application-orientation systems Component-based systems EPOS Design Framework Generation Tools Conclusion

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 3 high performance X all purpose, global, generic Introduction There is no best “general” solution Each (class of) application has particular demands

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 4 Applicaiton-orientation Each application deserves its own run-time support system Set of applications that will run on top of the operating system and their requirements Isn’t known until run-time => dynamic adaptation Can be determined before run-time => static configuration Parallel and embedded applications Adaptability and configurability Component-based?

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 5 Component-orientation component granularity many simple components customizability reusability performance “a queue link” “a file system” usability maintainability a few complex components

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 6 The Gap to Applications (Motivation for EPOS) component granularity many simple components What is this component for? What is the difference to that other one? How do I use it? Do I have to take this junk as well? The component I need is not there! a few complex components

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 7 EPOS: Embedded Parallel Operating System EPOS operating system Application-driven assemblage of system components EPOS components Statically configurable, application ready system abstractions EPOS and the real world Intelligent visual tools for configuration Invisibility Standard libraries (Posix files, libc, libstdc++, libm) Standard APIs (Posix threads, MPI)

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 8 System Abstraction system micro-components EPOS System Abstractions Application ready components Independent from execution scenario Examples: A thread on a given scheduling policy NOT a thread for one processor, or for multi- tasking

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 9 Scenario Adapters EPOS Scenario Adapters Adapt existing system abstractions for a given execution scenario Adapt system micro- components to grant the semantics dictated by a given execution scenario Examples: An SMP adapter A secure remote invocation adapter

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 10 task memory segment thread file synchronizer communicator Inflated Interfaces EPOS Inflated Interfaces Export system abstractions to applications Well-known to application programmers Comprehensive Promote requirement analysis Examples: thread communicator synchronizer Not a fat interface if intersection => subset

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 11 realization > partially realizeselectively realize key realization 1 > realization 3realization Partial and Selective Realization Relationships System configuration is basically restricted to the setting of selective realize keys

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 12 Wrapped No allocation or sharing control No cross-domain invocation Always embedded in the application Controlled Allocation and sharing control is possible Cross-domain invocation is possible Embedded in the application or packed in a kernel EPOS Framework Static metaprogrammed Metaprograms run at compile-time (Almost) no run-time overhead Implemented as C++ templates System abstraction implementation

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 13 inflated interface scenario adapter > wrapper realization > Application EPOS Framework Wrapped System Abstraction

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 14 basic stub message exchange stubprocedure call stubInflated interface > stub > server > realization basic server message exchange serverprocedure call server handle > id > message > id state Application System EPOS Framework Controlled System Abstraction > scenario adapter

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 15 Automatic Generation Application refers to inflated interfaces Requirement analyzer parses the application searching for inflated interfaces references Which interfaces are referred to? How they are referred to? Expert system select the realizations that better match the referred inflated interfaces An application-oriented operating system is compiled

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 16 syntactic analyzer tasks segments threadsmailboxes mutexfiles complex application program code = new Segment(buffer, size); task = new Task(code, data); thread = new Thread(task, &entry_func, priority, SUSPENDED, arguments); mutex->entry(); Mailbox mailbox; mailbox >> message; File file(name); file << mailbox; Requirement Analysis

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 17 Requirement Analysis flat memorylinks syntactic analyzer real application program (MPI) Channel link(destination); link << mesage;

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 18 Context Information We need context information new Thread(task, &func) => location? mailbox protocol? Absence of Task => single-task? Buildup databases Scenario dependencies Target machine description

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 19 Execution Scenario execution scenario += tasks segments threadsmailboxes monitorsfiles required Inflated interfaces

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 20 Application-oriented EPOS application interfaces scenario adapters system micro-componentssystem abstractions

German National Research Center for Information Technology Research Institute for Computer Architecture and Software Technology 21 Conclusions EPOS doesn’t grant the tailored OS to be optimal When several realizations fulfill the requirements, the selection is arbitrary Profiling could help EPOS framework overhead is close to zero Tools are being implemented System abstraction repository is growing First real applications are being negotiate

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