1 / 5

Winter 03-04 projects – Distributed Shared Memory (DSM)

Winter 03-04 projects – Distributed Shared Memory (DSM). Superviser: Liran Liss liranl@tx.technion.ac.il Meyer 764, (829)4706. Software DSM. Emulates shared memory across a computing cluster Software DSMs implement an invalidation based protocol using OS page protection

jhank
Télécharger la présentation

Winter 03-04 projects – Distributed Shared Memory (DSM)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Winter 03-04 projects – Distributed Shared Memory (DSM) Superviser: Liran Liss liranl@tx.technion.ac.il Meyer 764, (829)4706

  2. Software DSM • Emulates shared memory across a computing cluster • Software DSMs implement an invalidation based protocol using OS page protection • Execution example… SAN 0x123000 0x123000 0x123000 R RW X R R X X X R X RW R Write

  3. Some observations: • The large page size can introduce “false sharing”. Possible solutions: • Relaxed consistency models • Multiview • Even without false sharing: a lot of page faults produce substantial overhead  Use pattern recognition techniques to perform smart prefetching (Project 1) • Application data is transferred from well known virtual memory locations  Use state-of-the-art user-level networking hardware to transfer data efficiently without involving the processor (Project 2) SAN 0x123000 0x123000 0x123000 R RW X X R X X R X RW X RW

  4. User-level networking (Infiniband) Application Virtual Memory Pinned Memory • Supported semantics: • Message-passing • Remote DMA (RDMA) • Asynchronous processing model that offloads CPU • Queue pairs (QPs) • Completion queues (CQs) • Specified by HCA Verbs • HW Features: • Channel mutliplexing • Reliable transport • Flow control Send Work Queue Verbs Consumer QP WQE WQE WQE Work Request To the fabric Receive Work Queue WQE WQE WQE Work Completion Completion Queue HCA HW CQE CQE CQE

  5. Adaptive granularity (Niv & Schuster)

More Related