Speculative DMA for Architecturally Visible Storage in Instruction Set Extensions Theo KluterEPFL Philip BriskEPFL Paolo IenneEPFL Edoardo CharbonEPFL

2 Motivation

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8 DMA in DMA out

9 Motivation

10 Motivation

11 Motivation

12 Motivation

13 Motivation

14 Contents Motivation Ensuring coherence Speculative DMA Opportunistic Speculative DMA Conclusion Questions

15 Ensuring coherence

16 Ensuring coherence

17 Ensuring coherence

18 Ensuring coherence

19 Ensuring coherence

20 Ensuring coherence

21 Ensuring coherence

22 Ensuring coherence

23 Ensuring coherence

24 Ensuring coherence

25 Contents Motivation Ensuring coherence Speculative DMA Opportunistic Speculative DMA Conclusion Questions

26 Speculative DMA

27 Speculative DMA

28 Speculative DMA

29 Speculative DMA

30 Speculative DMA

31 Contents Motivation Ensuring coherence Speculative DMA Opportunistic Speculative DMA Conclusion Questions

32 Opportunistic Speculative DMA ?

33 Opportunistic Speculative DMA

34 Opportunistic Speculative DMA

35 Opportunistic Speculative DMA

36 Opportunistic Speculative DMA

37 Contents Motivation Ensuring coherence Speculative DMA Opportunistic Speculative DMA Conclusion Questions

38 Conclusion Coherence is a serious concern Use existing hardware coherence protocols Limited hardware overhead Single- and multi-processor solution Tanglable speed-up possible by profiling

39 Contents Motivation Ensuring coherence Speculative DMA Opportunistic Speculative DMA Conclusion Questions ?