tornado and vxworks l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Tornado and VxWorks PowerPoint Presentation
Download Presentation
Tornado and VxWorks

Loading in 2 Seconds...

play fullscreen
1 / 54

Tornado and VxWorks - PowerPoint PPT Presentation


  • 1051 Views
  • Uploaded on

Tornado and VxWorks. Tornado and VxWorks. Tornado-VxWorks Architecture The Real-Time, Multitasking OS Intertask Synchronization and Communication The Project Facility The Debugging Tools The Networking Stack. What is Tornado?. Development and Debugging Tools. Real-Time,

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Tornado and VxWorks' - JasminFlorian


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
tornado and vxworks2
Tornado and VxWorks

Tornado-VxWorks Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

what is tornado
What is Tornado?

Development and Debugging

Tools

Real-Time,

Multitasking

OS

Networking

Copyright © Wind River Systems, Inc.

tornado architecture hw target

Host

Target

Registry

Tool

VxWorks

Target

Server

Tool

Target Agent

Tool

Tornado Architecture - HW Target
  • The tools, registry, and target server can run on different hosts

Copyright © Wind River Systems, Inc.

tornado architecture simulator target
Tornado Architecture - Simulator Target

Host

  • VxWorks runs as a process under the host OS
  • The simulator architecture provides no emulation of instruction, native compilers are used

Registry

Tool

VxWorks

Target

Server

Tool

Target Agent

Tool

Copyright © Wind River Systems, Inc.

tornado and vxworks6
Tornado and VxWorks

Tornado Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

what is a task
What is a Task?
  • A task is a
    • Kernel object dynamically created at runtime
    • Logical entity consisting of a Task Control Block (TCB) data structure and stack space
    • An independent thread of execution
  • A task is not a function
    • However, a special purpose function (typically designed with an endless loop) is used for the task’s entry point
    • Functions execute within the context of tasks
    • The VxWorks routine taskSpawn() invokes the entry point function foo and gives the task it’s thread of “liveness”

foo()

{ for (;;)

{ waitForData( );/* Until external event occurs */ processData( ); }}

Copyright © Wind River Systems, Inc.

creating a task
Creating a Task

Copyright © Wind River Systems, Inc.

multitasking
Multitasking
  • Separate tasks are created to perform different system requirements
    • For example, data acquisition and data computation
  • Each task alternates between “ready” and “waiting”
    • A “task manager” (the multitasking kernel) is therefore required
  • VxWorks allows a task to wait for
    • A specified time delay (Delay)
    • An event such as an interrupt (Pend)

Copyright © Wind River Systems, Inc.

task states
Task States

Copyright © Wind River Systems, Inc.

multitasking kernel
Multitasking Kernel
  • The “wind” kernel is that part of VxWorks which directly manages tasks
  • It allocates the CPU to tasks according to the VxWorks scheduling algorithm
  • It uses Task Control Blocks (TCBs) to keep track of tasks
    • One per task
    • Declared as WIND_TCB data structure in taskLib.h
    • O.S. control information
      • state, task priority, delay timer,breakpoint list, error status,I/O redirections
    • CPU Context Information
      • PC, SP, CPU registers, FPU registers

Copyright © Wind River Systems, Inc.

kernel operation
Kernel Operation

Scheduler

Copyright © Wind River Systems, Inc.

multitasking facilities
Multitasking Facilities

Copyright © Wind River Systems, Inc.

tornado and vxworks14
Tornado and VxWorks

Tornado-VxWorks Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

intertask synchronization
Intertask synchronization
  • In a multitasking environment, facilities to achieve mutual synchronization are needed
    • Producer-consumer architecture
    • Client-server architecture
  • In VxWorks, intertask synchronization is achieved using
    • Binary Semaphores
    • Message Queues
    • Events
    • Pipes
  • Some intertask synchronization facilities (queues and pipes) also enable data transmission (intertask communication)

Copyright © Wind River Systems, Inc.

binary semaphores
Binary Semaphores
  • Binary semaphores exist in one of two states
    • Full (synchronizing event has occurred)
    • Empty (synchronizing event has not occurred)
  • Intertask synchronization is obtained by creating an empty, binary semaphore for the synchronizing event
    • The task waiting for the event calls semTake( ) and blocks until the semaphore is given
    • The task or interrupt service routine detecting the event calls semGive( ), which unblocks the waiting task

Copyright © Wind River Systems, Inc.

message queues

Task A

Task B

Message Queues
  • Message queues are kernel objects used for passing information between tasks
  • Message queues provide a FIFO buffer of messages
  • The task waiting for the synchronization message calls msgQueueReceive( ) and blocks until a message is on the queue
  • The task sending the synchronization message calls msgQueueSend( ), which unblocks a pending task

Copyright © Wind River Systems, Inc.

pipes
Pipes
  • Pipes provide an alternative interface to the message queue facility in the VxWorks I/O system
  • Tasks block
    • When they read from an empty pipe, until data is available
    • When they write to a full pipe, until there is space available
  • Similar to their use of message queues, interrupt service routines can write to a pipe, but cannot read from it

Copyright © Wind River Systems, Inc.

events
Events
  • VxWorks events are means of synchronization between
    • Tasks and tasks
    • Interrupt service routines and tasks
    • VxWorks objects (binary semaphores and message queues) and tasks
  • Only tasks can receive events, whereas tasks, interrupt service routines or VxWorks objects can send events
  • Events are synchronous in nature
    • The receiving task pends while waiting for the events to be sent
  • Events allow a task to wait simultaneously on multiple resources
    • For example, events can be sent by semaphores, message queues and other tasks

Copyright © Wind River Systems, Inc.

mutual exclusion semaphores
Mutual Exclusion Semaphores
  • Mutually exclusive access to shared resources is provided in VxWorks by mutual-exclusion semaphores (mutexes)
  • VxWorks mutexes are designed to address issues inherent to mutual exclusion, like
    • Priority inversion
    • Deletion safety
    • Recursive access to the shared resource
    • Semaphore ownership
  • Each critical section of the code has to be protected with mutexes, by having a task
    • Take the mutex before accessing the code
    • Give the mutex after having accessed it

Copyright © Wind River Systems, Inc.

counting semaphores
Counting Semaphores
  • Counting semaphores are similar to binary semaphores, except that they keep track of the number of times the semaphore is given or taken
    • Every time the semaphore is given, the count is incremented
    • Every time the semaphore is taken, the count is decremented
    • When the count reaches zero, a task that tries to take the semaphore is blocked
  • Counting semaphores are useful for guarding multiple copies of resources

Copyright © Wind River Systems, Inc.

signals
Signals
  • Signals asynchronously alter the control flow of a task
    • An interrupt service routine or a task can send a signal to a task
    • The task which has received the signal will asynchronously execute a signal handler
    • The signal handler executes in the receiving task’s context and makes use of the task’s stack
    • If no signal handler is installed, the received signal is ignored
  • Since signals are asynchronous in nature, they are more appropriate for error and exception handling than as a general-purpose intertask communication mechanism

Copyright © Wind River Systems, Inc.

tornado and vxworks23
Tornado and VxWorks

Tornado-VxWorks Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

projects
Projects
  • The project facility allows one to manage two project types
    • Bootable projects
      • To configure and build a VxWorks image
    • Downloadable projects
      • To build and download application modules to a running target
  • Projects can be grouped together in Workspaces
  • For each project more than one build specification can be used

Copyright © Wind River Systems, Inc.

bootable projects
Bootable projects
  • Bootable projects are used to create a new, customized VxWorks image
    • The system image consists of all desired system modules linked together in a single, non-relocatable object module with no unresolved external references
    • The image can be customized by adding or removing VxWorks components from the Workspace GUI
  • A bootable project is created specifying
    • A BSP
    • A toolchain (GNU or Diab)

Copyright © Wind River Systems, Inc.

downloadable projects
Downloadable Projects
  • Downloadable projects are used to create relocatable object modules that can be downloaded and dynamically linked to VxWorks
    • Module downloading and dynamic linking is performed by the Target Server, which maintains a host-resident target’s symbol table
  • Downloadable projects
    • Are created by specifying a toolchain
      • GNU or Diab
    • Allow “on the fly” development
      • Modules can iteratively be downloaded, tested and debugged without rebooting the target system

Copyright © Wind River Systems, Inc.

project facility workspace window
Project Facility Workspace Window
  • 3 Workspace window views

Copyright © Wind River Systems, Inc.

tornado and vxworks28
Tornado and VxWorks

Tornado-VxWorks Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

host resident debugging tools
Host-Resident Debugging Tools
  • WindShell Command Shell
    • Provides command-line based, interactive access to all run-time facilities
  • Browser
    • System-object viewer, graphical companion to WindShell
  • CrossWind Debugger
    • Remote source-level debugger
    • Extended version of the GNU source-level debugger (GDB)
  • WindView Software Logical Analyzer
    • Dynamic visualization tool

Copyright © Wind River Systems, Inc.

windshell
WindShell
  • WindShell allows one to
    • Access all VxWorks facilities by allowing calls to any VxWorks routines
      • For example,
        • Spawning tasks
        • Creating VxWorks objects like semaphores, message queues, and pipes
    • Download object modules to the target system
    • Perform assembly-level debugging
    • Create and examine variables symbolically
    • Examine and modify memory

Copyright © Wind River Systems, Inc.

windshell31
WindShell

Copyright © Wind River Systems, Inc.

browser
Browser
  • The browser monitors the state of a target
  • It shows detailed information on
    • Tasks
    • VxWorks objects (semaphores, message queues, ...)
    • Stack usage by all task on the target
    • Target CPU usage by task
    • Object-module structure and symbols
    • Interrupt vectors
  • The displays are snapshots, which can be updated interactively
    • Alternatively, the Browser can be configured to automatically update its display at specified intervals

Copyright © Wind River Systems, Inc.

browser33
Browser

Copyright © Wind River Systems, Inc.

crosswind
CrossWind
  • CrossWind is a source level, graphical, debugging front-end using an enhanced version of GDB as its debugging engine
  • It allows two debugging strategies
    • Task mode debugging
      • One task runs under debug control, while other tasks are not affected
      • CrossWind can either
        • Attach to a running task, or
        • Start a new task under debugger control
    • System mode debugging
      • Whenever a task hits a breakpoint, the whole system stops
      • This is useful to debug tasks, interrupt service routines and pre-kernel execution

Copyright © Wind River Systems, Inc.

crosswind35
CrossWind

Copyright © Wind River Systems, Inc.

windview 2 2
WindView 2.2
  • WindView allows one to study dynamic interactions of all the elements of complex, real-time systems

Copyright © Wind River Systems, Inc.

windview 2 237
WindView 2.2
  • The WindView graph provides manageable access to important application information
  • WindView allows
    • Scrolling the information forward and backward in time
    • Zooming in/out
    • Tailoring the display to only focus on the tasks and events of interest
    • Setting locks on certain events and searching for their successive occurrences

Copyright © Wind River Systems, Inc.

windview 2 2 example
WindView 2.2 Example

Copyright © Wind River Systems, Inc.

problem solving with windview 2 2
Problem Solving with WindView 2.2
  • WindView allows to
    • Detect race conditions, deadlocks, CPU starvation and other problems related to task interaction
    • Determine application responsiveness and performance
    • See cyclic patterns in application behavior
    • Conduct post-mortem analysis of failed systems
    • Detect memory leaks

Copyright © Wind River Systems, Inc.

tornado and vxworks40
Tornado and VxWorks

Tornado-VxWorks Architecture

The Real-Time, Multitasking OS

Intertask Synchronization and Communication

The Project Facility

The Debugging Tools

The Networking Stack

Copyright © Wind River Systems, Inc.

vxworks network components
VxWorks Network Components

netDrv

Target

server

NFS

Application layer

rlogin

telnet

rsh

ftp

RPC

Application programming

interface

zbuf

Sockets

TCP

UDP

Transport layer

IP

Network layer

PPP

Shared Memory

Network

MUX

Link layer

Ethernet

Copyright © Wind River Systems, Inc.

shared memory backplane network

vx3

vx2

vx1

Shared-Memory Backplane Network
  • This allows multiple processors to communicate over their common backplane as if they were communicating over a network by using a standard network driver

host

Ethernet

Shared-Memory

Network

Backplane (e.g. VME, PCI)

Copyright © Wind River Systems, Inc.

mux the network driver interface
MUX – The Network Driver Interface
  • This interface decouples the link layer and the network layer
    • The network protocol does not need to be modified when adding new network dirvers
    • A new network protocol can be added without modifying the existing MUX-based network driver interfaces

Copyright © Wind River Systems, Inc.

tcp ip protocol suite
TCP/IP Protocol Suite
  • Based on the 4.4 BSD TCP/IP release, the TCP/IP protocol suite comprises
    • UDP – User Datagram Protocol
      • Low-overhead delivery mechanism of datagrams, used by several applications like BOOTP, DHCP, DNS, TFTP, ...
    • TCP – Transmission Control Protocol
      • Reliable, end-to-end transmission mechanism, used by Telnet, Rlogin, FTP, ...
    • IP – Internet Protocol
      • Hop-by-hop protocol to transmit datagrams
    • ICMP – Internet Control Messagge Protocol
      • Reports unexpected events in data transfer, used by ping
    • IGMP – Internet Group Management Protocol
      • Used to support multicasting

Copyright © Wind River Systems, Inc.

sockets
Sockets
  • Sockets allow processes to communicate within a single CPU, across an Ethernet, across a backplane or across any connected combination of networks
  • VxWorks provides
    • BSD Sockets
      • Datagram Sockets (UDP)
      • Stream Sockets (TCP)
      • Raw Sockets
    • Zbuf Sockets
      • An alternative set of sockets based on a data abstraction called zbuf, zero-copy buffer
      • Applications can read and write BSD sockets without copying data between application buffers and network buffers

Copyright © Wind River Systems, Inc.

remote access applications
Remote Access Applications
  • RSH – Remote Command Execution
    • Allows a VxWorks application to run commands on a remote system and receive the command results on standard output and error over socket connection
      • Only the client side implementation is provided
      • A server running on the remote system is assumed
  • FTP – File Transfer Protocol
    • Both client and server applications are provided
  • NFS – Network File System
    • Server component
      • A target running VxWorks act as a file server for any system that runs an NFS client
    • Client component
      • A target running VxWorks can mount a remote file system

Copyright © Wind River Systems, Inc.

remote access applications cont d
Remote Access Applications (cont’d)
  • TFTP – Trivial File Transfer Protocol
    • Client and Server applications are provided
    • Unlike FTP or RSH, TFTP does not require any authentication
  • Rlogin – Remote Login
    • On a VxWorks terminal, rlogin( ) gives users the ability to log in to remote systems on the network
    • The remote login daemon, rlogind(), allows remote users to log in to VxWorks
  • Telnet
    • The server application only is provided
  • RPC – Remote procedure call
    • RPC implements a client-server model of task interaction
    • A client requests a remote service from a server and waits for a reply

Copyright © Wind River Systems, Inc.

dns and sntp
DNS and SNTP
  • DNS – Domain Name System
    • DNS is a distributed database used by TCP/IP applications that maps hostnames to IP addresses
  • SNTP – Simple Network Time Protocol
    • Client and server components are provided
      • The client is normally used to maintain its system internal clock accuracy based on time values reported by one or more servers
      • The server provides time information to other systems

Copyright © Wind River Systems, Inc.

bootp bootstrap protocol
BOOTP – Bootstrap Protocol
  • The BOOTP server
    • Retrieves boot information from the Bootp Database (bootptab)
    • Supplies an Internet host with an IP address and related configuration information
      • The IP address is permanently assigned
  • The BOOTP client
    • Uses broadcasts to discover an appropriate server
    • Lets a target retrieve a set of boot parameters like an IP address and a filename of the bootable image
  • Both client and server components are provided
  • BOOTP is implemented on top of UDP

Copyright © Wind River Systems, Inc.

dhcp dynamic host configuration protocol
DHCP – Dynamic Host Configuration Protocol
  • Like BOOTP, DHCP allows the permanent allocation of configuration parameters to specific clients
  • However, DHCP also supports the assignment of a network address for a finite lease period
  • VxWorks includes a DHCP client, server, and relay agent
  • The client can retrieve one or more sets of configuration parameters from either a DHCP or BOOTP server
  • The server can process both BOOTP and DHCP messages
  • The DHCP relay agent provides forwarding of DHCP and BOOTP messages across subnet boundaries

Copyright © Wind River Systems, Inc.

ip routing
IP Routing
  • If the destination is directly connected to the sender (e.g., a point-to-point link) or on a shared network (e.g., Ethernet), then IP datagrams are sent directly to the destination
    • Otherwise, the sender sends the IP datagrams to a default router, and lets the router deliver them to destination
  • Each router maintains a routing table, which is used to deliver the IP datagrams to either
    • A local IP address, for a direct route, or
    • The next-hop router IP address, for an indirect route

Copyright © Wind River Systems, Inc.

dynamic routing protocols
Dynamic Routing Protocols
  • Dynamic routing occurs when routers talk to adjacent routers, informing each other of what network each router is connected to
  • Entries in the routing tables change dynamically as routes change over time
  • The Routing Information Protocol (RIP) is provided with VxWorks
    • This is intended for small to medium-sized networks
      • The longest path must be less than 16 hops
    • It uses a distance-vector protocol
      • It contains a vector of distances as the hop count
    • RIP version 1 and 2 are supported

Copyright © Wind River Systems, Inc.

summary
Summary
  • Tornado’s three components
    • VxWorks, real-time, multitasking operating system
      • Priority-based, preemptive scheduling algorithm
      • Intertask synchronization and communication services
    • Project facility and debugging tools
      • Bootable and downloadable projects
    • Networking
      • Connects hosts and targets during development and debugging
      • TCP/IP stack
      • Rich set of network applications and protocols

Copyright © Wind River Systems, Inc.

references
References
  • Manuals available either in the Tornado on-line help, or via the Wind River Bookstore at: www.windriver.com/windsurf/bookstore
    • Tornado User’s Guide
    • WindView User’s Guide and User’s Reference
    • VxWorks Programmer’s Guide
    • VxWorks OS Libraries
    • VxWorks Network Programmer’s Guide

Copyright © Wind River Systems, Inc.