simple_v_extension/simple_v_chennai_2018.tex

   1
   2 \documentclass[slidestop]{beamer}
   3 \usepackage{beamerthemesplit}
   4 \usepackage{graphics}
   5 \usepackage{pstricks}
   6
   7
   8 \title{Simple-V RISC-V Extension for Vectorisation and SIMD}
   9 \author{Luke Kenneth Casson Leighton}
  10
  11
  12 \begin{document}
  13
  14 \frame{
  15    \begin{center}
  16     \huge{Simple-V RISC-V Extension for Vectors and SIMD}\\
  17     \vspace{48pt}
  18     \Large{Flexible Vectorisation}\\
  19     \Large{Chennai 9th Workshop}\\
  20     \vspace{24pt}
  21     \large{\today}
  22   \end{center}
  23 }
  24
  25 \frame{\frametitle{Why another Vector Extension?}
  26
  27  \begin{itemize}
  28    \item RVV very heavy-duty (excellent for supercomputing)\vspace{10pt}
  29    \item Simple-V abstracts parallelism (based on best of RVV)\vspace{10pt}
  30    \item Graded levels: hardware or software-emulation\vspace{10pt}
  31    \item Even Compressed instructions become vectorised\vspace{10pt}
  32   \end{itemize}
  33   What Simple-V is not:\vspace{12pt}
  34    \begin{itemize}
  35    \item A full supercomputer-level Vector Proposal\vspace{12pt}
  36    \item A replacement for RVV (designed to be augmented)\vspace{12pt}
  37   \end{itemize}
  38 }
  39
  40 \frame{\frametitle{Quick refresher on SIMD}
  41
  42  \begin{itemize}
  43    \item SIMD very easy to implement\vspace{10pt}
  44    \item Parallelism is in the ALU\vspace{10pt}
  45    \item Negligeable impact for rest of core\vspace{10pt}
  46   \end{itemize}
  47   Where SIMD Goes Wrong:\vspace{12pt}
  48    \begin{itemize}
  49    \item See "Why SIMD considered harmful"\vspace{12pt}
  50    \item (Corner-cases alone are extremely complex)\vspace{12pt}
  51    \item O($N^{6}$) ISA proliferation\vspace{12pt}
  52   \end{itemize}
  53 }
  54
  55 \frame{\frametitle{Quick refresher on RVV}
  56
  57  \begin{itemize}
  58    \item Extremely powerful (extensible to 256 registers)\vspace{10pt}
  59    \item Supports polymorphism, several datatypes (inc. FP16)\vspace{10pt}
  60    \item Requires a separate Register File\vspace{10pt}
  61    \item Can be implemented as a separate pipeline\vspace{10pt}
  62   \end{itemize}
  63   However...\vspace{12pt}
  64    \begin{itemize}
  65    \item 98 percent opcode duplication with rest of RV (CLIP)\vspace{12pt}
  66    \item Extending RVV requires customisation\vspace{12pt}
  67   \end{itemize}
  68 }
  69
  70
  71 \frame{\frametitle{How is Parallelism abstracted?}
  72
  73  \begin{itemize}
  74    \item Almost all opcodes removed in favour of implicit "typing"\vspace{10pt}
  75    \item Primarily at the Instruction issue phase (except SIMD)\vspace{10pt}
  76    \item Standard (and future, and custom) opcodes now parallel\vspace{10pt}
  77      \end{itemize}
  78   What Simple-V is not:\vspace{12pt}
  79    \begin{itemize}
  80    \item A full supercomputer-level Vector Proposal\vspace{12pt}
  81    \item A replacement for RVV (designed to be augmented)\vspace{12pt}
  82   \end{itemize}
  83 }
  84
  85
  86 \frame{\frametitle{How are SIMD Instructions Vectorised?}
  87
  88  \begin{itemize}
  89    \item SIMD ALU(s) primarily unchanged\vspace{10pt}
  90    \item Predication is added to each SIMD element\vspace{10pt}
  91    \item End of Vector implicitly enables predication\vspace{10pt}
  92      \end{itemize}
  93   Considerations:\vspace{12pt}
  94    \begin{itemize}
  95    \item Many SIMD ALUs possible (parallel execution)\vspace{12pt}
  96    \item Very long SIMD ALUs could waste die area (short vectors)\vspace{12pt}
  97    \item Implementor free to choose (API remains the same)\vspace{12pt}
  98   \end{itemize}
  99 }
 100
 101 \frame{\frametitle{Including a plot}
 102  \begin{center}
 103 %  \includegraphics[height=2in]{dental.ps}\\
 104   {\bf \red Dental trajectories for 27 children:}
 105  \end{center}
 106 }
 107
 108 \frame{\frametitle{Creating .pdf slides in WinEdt}
 109
 110  \begin{itemize}
 111    \item LaTeX [Shift-Control-L]\vspace{12pt}
 112    \item dvi2pdf [click the button]\vspace{24pt}
 113   \end{itemize}
 114   To print 4 slides per page in acrobat click\vspace{12pt}
 115    \begin{itemize}
 116    \item File/print/properties\vspace{12pt}
 117    \item Change ``pages per sheet'' to 4\vspace{12pt}
 118   \end{itemize}
 119 }
 120
 121 \frame{
 122   \begin{center}
 123     {\Huge \red The end}
 124   \end{center}
 125 }
 126
 127
 128 \end{document}