Giotto A Time-Triggered Language for Embedded Programming Thomas A. Henzinger, Benjamin Horowitz Christoph M. Kirsch, Rupak Majumdar UC Berkeley

Embedded Programming Giotto aims at hard real-time applications Giotto is time-triggered Giotto is platform independent Giotto consists of ports, tasks, modes Giotto works, with VxWorks, Ptolemy

Functionality & Timing Control Engineer Control Design Application designs validates simulates Software Engineer Platform Implementation decomposes implements tests First Challenge

Compilation Platform Implementation Second Challenge Software Engineer decomposes implements tests

A Task

Abstract Syntax of a Task f

f State

Abstract Syntax of a Task fInput ports State

Abstract Syntax of a Task fInput ports State Output ports

Abstract Syntax of a Task fInput ports State Output ports Frequency

Semantics of a Task fInput ports State Output ports Frequency 10ms

Semantics of a Task fInput ports State Output ports Time Task Frequency 10ms

Semantics of a Task fInput ports State Output ports Time Task Frequency 10ms

Semantics of a Task fInput ports State Output ports Time Task time t Frequency 10ms

Semantics of a Task fInput ports State Output ports Time Task time t Frequency 10ms time t+10ms

Semantics of a Task fInput ports State Output ports Time Task time t Frequency 10ms time t+10ms Don’t care

A Connection Input portsOutput portsf State

Abstract Syntax of a Connection f State Constant

Abstract Syntax of a Connection f State Input portOutput port

Semantics of a Connection f State f

Semantics of a Connection f State f Time Task

Semantics of a Connection f State f Time Task time t

Semantics of a Connection f State f Time Task time time t

Semantics of a Connection f State f Time Task time time t 0 time

Two Tasks PInput portsOutput ports

Two Tasks PInput portsOutput ports QInput portsOutput ports

Connections P Q

P Q

P Q

Different Periodicity P Q

Time Task P QQ

Semantics Time Task P QQ

Semantics Time Task P QQ tt+10ms

Semantics Time Task P QQ tt+10mst

Semantics Time Task P QQ tt+10mstt+5ms

Semantics Time Task P QQ tt

Connections P Q

Semantics Time Task P QQ tt

Connections P Q

Semantics Time Task P QQ tt

Semantics Time Task P QQ t+5mst Don’t care

Semantics Time Task P QQ t+5ms

Semantics Time Task P QQ t+5ms

Semantics Time Task P QQ t+5ms

Semantics Task P QQ t+10ms

Semantics Task P QQ t+10ms

Semantics Task P QQ t+10ms

Theory ! A Giotto program is a single set of tasks, so far Is this enough?

Theory = Practice ? Yes, we have sufficient computation and communication resources! => A single set of tasks is enough

Theory = Practice ? Yes, we have sufficient computation and communication resources! => A single set of tasks is enough Fin

Theory = Practice ? Yes, we have sufficient computation and communication resources! => A single set of tasks is enough Fin No, we have to share resources! => with modes

Practice ! A mode is a set of tasks. A Giotto program is a set of modes. A Giotto program is a partitioning of the set of all required tasks.

FAQ: Time vs. Events Q: How about events? A: Use modes!

A Mode

Abstract Syntax of a Mode P Q

P Q

P Q

P Q Entry Port

Abstract Syntax of a Mode P Q Entry Port Period

Semantics of a Mode P Q Entry Port Period 10ms 1 2

Concrete Syntax mode m ( ) period 10 ms { taskfreq 1 do int x = P ( ) ; taskfreq 2 do int y = Q ( x, y ) ; }

A Mode Switch MM’

M Predicate Abstract Syntax of a Mode Switch

MM’ Predicate Abstract Syntax of a Mode Switch Frequency

MM’ Predicate Abstract Syntax of a Mode Switch Frequency Connection

MM’ Predicate Abstract Syntax of a Mode Switch Frequency 5ms Connection

Mode M P Q Period 10ms 1 2

Mode M P Q Period 10ms 1 2 Connection

Mode M’ Connection

Mode M’ P 1 Connection

Mode M’ P R 1 4 Connection

Mode M’ P R 1 4 Connection

Mode M’ P R 1 4 Connection

Mode M’ P R 1 4 Connection

Mode M’ P R 1 4 Connection Period 10ms

Concrete Syntax start m ( ) { mode m ( ) period 10 ms entryfreq 1 { taskfreq 1 do int x = P ( ) ; taskfreq 2 do int y = Q ( x, y ) ; exitfreq 2 if y = 5 then m’ ( y ) ; } mode m’ ( int z ) period 10 ms entryfreq 2 { taskfreq 1 do int x = P ( ) ; taskfreq 4 do int u = R ( x, z ) ; }

Semantics of a Mode Switch Task P QQ Time

Semantics of a Mode Switch Task P QQ Mode t+10mst+10ms

Semantics of a Mode Switch Task P QQ Mode t+5mst+5ms Time

Semantics of a Mode Switch Task P Q Time Mode t+5ms

Mode M’ P R 1 4

Semantics of a Mode Switch Task P Q t+5ms Time R t+5ms

Semantics of a Mode Switch Task P Q t+5ms Time RR t+5mst+7.5ms

Semantics of a Mode Switch Task P Q t+5ms RR t+7.5mst+10ms

Semantics of a Mode Switch Task P Q t+5ms RR Time

Mode M P Q 1 2 Connection

Semantics of a Mode Switch Task P Q t+5ms RR Time

Semantics of a Mode Switch Task P QRR Mode Switch t+5ms Time

Mode M’ P R 1 4 Connection

Semantics of a Mode Switch Task P Q t+5ms RR Time

Mode M’ P R 1 4 Connection

Semantics of a Mode Switch Task P Q t+5ms RR Time

Mode M’ P R 1 4 Connection

Semantics of a Mode Switch Task P Q t+5ms RR Time

Semantics of a Mode Switch Task P QRR Time t+7.5ms

Semantics of a Mode Switch Task P QRR Time t+7.5ms

Semantics of a Mode Switch Task P QRR Time t+7.5ms

Semantics of a Mode Switch Task P QRR Time t+7.5ms

Semantics of a Mode Switch Task P QRR t+10ms

Semantics of a Mode Switch Task P QRR t+10ms

Semantics of a Mode Switch Task P QRR t+10ms

Semantics of a Mode Switch Task P QRR t+10ms

Functionality & Timing Control Engineer Control Design Application designs validates simulates Software Engineer Platform Implementation decomposes implements tests First Challenge

Compilation Platform Implementation Second Challenge Software Engineer decomposes implements tests

Annotated Giotto Giotto Compiler Giotto Program Platform

Giotto-Architecture Giotto Compiler Hosts, Nets, Performance Giotto Program Giotto-A Program Platform

Giotto-Scheduler Giotto Compiler Task to Host, Priority Hosts, Nets, Performance Giotto Program Giotto-A Program Giotto-AS Program Platform

Giotto-Communication Giotto Program Giotto Compiler Giotto-A Program Platform Giotto-AS Program Giotto-ASC Program Task to Host, Priority Hosts, Nets, Performance Connection to Net, TDMA

Platform Dependency Task P QQ Time

Platform Dependency Task P QQ Time Computation

Giotto-AS Task P QQ Time Host A

Giotto-AS Task P QQ Time Host A 2. 1.

Platform Dependency Task P QRR Time

Platform Dependency Task P QRR Time Communication

Platform Dependency Task P QRR Time Communication

Giotto-ASC Task P QRR Time Host A Host BCC

Giotto-ASC Task P QRR Time Host A Host BCC Network C

Giotto-ASC Task P QRR Time Host A Host BCC Network C t+10mst

Giotto-ASC Task P QRR Time Host A Host BCC Network C t+10mst

Giotto-ASC Task P QRR Time Host A Host BCC Network C t+10mst

Summary Control Design Application Platform Implementation Functionality & Timing Control Engineer Software Engineer Compilation

Demo