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K42 Internals. Dilma da Silva for K42 group IBM TJ Watson Research. K42 Goals. Scalability Flexibility/customizability Framework for OS research Linux API and ABI and kernel module compatible Available to collaborators under LGPL Maintainability/extensibility.
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K42 Internals Dilma da Silva for K42 group IBM TJ Watson Research FastOS PI Meeting/Workshop
K42 Goals • Scalability • Flexibility/customizability • Framework for OS research • Linux API and ABI and kernel module compatible • Available to collaborators under LGPL • Maintainability/extensibility FastOS PI Meeting/Workshop
OS function in user-level library examples: timers, thread library... allows OS services to be customized for applications with specialized needs avoids interactions with kernel/servers, reduces space/time overhead in kernel/servers Object-oriented design at all levels Application Application Linux emulation Linux emulation OS lib OS lib Servers Micro-kernel Structure FastOS PI Meeting/Workshop
Object-oriented design FastOS PI Meeting/Workshop
OO Design: MM Objects Region FCM FR Region Region Process Region FCM FR Region FCM: File Cache Management FR: File Representative HAT: Hardware Address Translation HAT FastOS PI Meeting/Workshop
Region FCM FR Process Region FCM FR Region Process Region FCM FR FastOS PI Meeting/Workshop
Region Region Region Region Region Region Specialization and Clustered Objects • OO design enables specialized implementations FastOS PI Meeting/Workshop
Clustered object infrastructure • Per-processor level of indirection avoids any centralized bottleneck • Provides library to simplify distributed implementation • Caching of local state • Incremental distribution of services • DHash Focus on locality! • Read-Copy-Update techniques • Use non-blocking synchronization • Avoid locking hierarchies FastOS PI Meeting/Workshop
Hot-swapping • change one system component/type for another without bringing system down • potential uses • scalability • performance • monitoring • extensibility • testing • Dynamic update: system availability FastOS PI Meeting/Workshop
Hot-Swapping/Dynamic Update • Depends on: • object-oriented structure of system • technology to establish a quiescent state • level of indirection • Implementation has no additional overhead • when not swapping an object • for objects not being swapped • Limitations: • is not instantaneous • initial prototype • Current work: coordinated swapping, interface changes, external policies... FastOS PI Meeting/Workshop
Independent workloads FastOS PI Meeting/Workshop
More hot-swapping Adaptive paging Adaptive file imp. FastOS PI Meeting/Workshop
Memclone benchmark: Memory intensive parallel application FastOS PI Meeting/Workshop
Performance monitoring • unified cheap scalable non-blocking tracing infrastructure for correctness and performance debugging • key parts of design transferred to LTT • post processing tools easy to develop: lock contention, sampling, time breakdown, visualization, caching effects, ... • in final numbers, disabled, but only %1.6 difference UP and 24 way FastOS PI Meeting/Workshop
Status http://www.research.ibm.com/K42 dilmasilva@us.ibm.com FastOS PI Meeting/Workshop