Your browser does not support JavaScript! Skip to main content
Free 30-day trial DO-178C Handbook RapiCoupling Preview DO-178C Multicore Training Multicore Resources
Rapita Systems
 

Industry leading verification tools & services

Rapita Verification Suite (RVS)

  RapiTest - Unit/system testing  RapiCover - Structural coverage analysis  RapiTime - Timing analysis (inc. WCET)  RapiTask - Scheduling visualization  RapiCoverZero - Zero footprint coverage analysis  RapiTimeZero - Zero footprint timing analysis  RapiTaskZero - Zero footprint scheduling analysis  RapiCouplingPreview - DCCC analysis

Multicore Verification

  MACH178  MACH178 Foundations  Multicore Timing Solution  RapiDaemons

Engineering Services

  V&V Services  Data Coupling & Control Coupling  Object code verification  Qualification  Training  Consultancy  Tool Integration  Support

Industries

  Civil Aviation (DO-178C)   Automotive (ISO 26262)   Military & Defense   Space

Other

RTBx Mx-Suite Software licensing Product life cycle policy RVS Assurance issue policy RVS development roadmap

Latest from Rapita HQ

Latest news

SAIF Autonomy to use RVS to verify their groundbreaking AI platform
RVS 3.22 Launched
Hybrid electric pioneers, Ascendance, join Rapita Systems Trailblazer Partnership Program
Magline joins Rapita Trailblazer Partnership Program to support DO-178 Certification
View News

Latest from the Rapita blog

How to certify multicore processors - what is everyone asking?
Data Coupling Basics in DO-178C
Control Coupling Basics in DO-178C
Components in Data Coupling and Control Coupling
View Blog

Latest discovery pages

control_tower DO-278A Guidance: Introduction to RTCA DO-278 approval
Picture of a car ISO 26262
DCCC Image Data Coupling & Control Coupling
Additional Coe verification thumb Verifying additional code for DO-178C
View Discovery pages

Upcoming events

DASC 2025
2025-09-14
DO-178C Multicore In-person Training (Fort Worth, TX)
2025-10-01
DO-178C Multicore In-person Training (Toulouse)
2025-11-04
HISC 2025
2025-11-13
View Events

Technical resources for industry professionals

Latest White papers

Mitigation of interference in multicore processors for A(M)C 20-193
Sysgo WP
Developing DO-178C and ED-12C-certifiable multicore software
DO178C Handbook
Efficient Verification Through the DO-178C Life Cycle
View White papers

Latest Videos

Rapita Systems - Safety Through Quality
Simulation for the Motorola 68020 microprocessor with Sim68020
AI-driven Requirements Traceability for Faster Testing and Certification
Multicore software verification with RVS 3.22
View Videos

Latest Case studies

GMV case study front cover
GMV verify ISO26262 automotive software with RVS
Kappa: Verifying Airborne Video Systems for Air-to-Air Refueling using RVS
Supporting DanLaw with unit testing and code coverage analysis for automotive software
View Case studies

Other Resources

 Webinars

 Brochures

 Product briefs

 Technical notes

 Research projects

 Multicore resources

Discover Rapita

Who we are

The company menu

  • About us
  • Customers
  • Distributors
  • Locations
  • Partners
  • Research projects
  • Contact us

US office

+1 248-957-9801
info@rapitasystems.com
Rapita Systems, Inc.
41131 Vincenti Ct.
Novi
MI 48375
USA

UK office

+44 (0)1904 413945
info@rapitasystems.com
Rapita Systems Ltd.
Atlas House
Osbaldwick Link Road
York, YO10 3JB
UK

Spain office

+34 93 351 02 05
info@rapitasystems.com
Rapita Systems S.L.
Parc UPC, Edificio K2M
c/ Jordi Girona, 1-3
Barcelona 08034
Spain

Working at Rapita

Careers

Careers menu

  • Current opportunities & application process
  • Working at Rapita
Back to Top Contact Us

Hardware acceleration features that make real-time hard – an overview

Breadcrumb

  1. Home
2012-10-29

New performance-enhancing features in modern processors can mean it is harder, not easier, to establish the worst-case execution time (WCET) of an application. Why is this happening?

Real-time systems and WCET

A real-time system is generally considered to be one where the correctness of the system depends not only on the result produced by that system, but also on the time at which that result is produced. In lots of systems, this translates directly into the concept of deadlines: a time by which a particular calculation must be complete or a result must be provided. Failure to meet deadlines causes problems, which depending on the system may range from inconvenient to catastrophic.

New hardware features and WCET

As systems have become larger and more complicated, it's become increasingly difficult to establish a value for the worst-case execution time. In part, this is because the software itself is larger and so there are a larger number of possible paths that the execution can follow. However, a significant difficulty is posed by new performance-enhancing features that are included in modern processors. Features like pipelined architectures, instruction and data caches and multicore processors make it much more difficult to establish the WCET and therefore, more difficult to guarantee that a system will meet its deadlines.

At first glance this may appear counter-intuitive: how can a feature that's supposed to improve performance make it more difficult to guarantee that deadlines are met? The key here is that the new hardware features are concerned with improving average case performance. Frequently the average case is improved dramatically, but at the expense of making it difficult to establish what happens in the worst-case.

This is because the state of the hardware, as well as the execution behaviour of the software, now has an effect on the execution time - for example, if a function requires access to some data, the execution time of that function will be less if that data is stored in a cache than it would be if the data must be retrieved from RAM. Often, methods to work around this behaviour lead to increasingly pessimistic results.

RapiTime and WCET

Developers of real-time systems spend lots of time and effort ensuring that their systems are schedulable, i.e. that they will always meet their deadlines. At Rapita, we help with this by providing RapiTime - a software toolset that allows the WCET for an application to be established. If you can prove that the system will meet all its deadlines even if everything runs for its WCET, you can be confident that the system won't fail because of a timing problem.

In future posts, we'll consider some of the technologies that make real-time analysis difficult in more detail, and examine some of the techniques that can be used with RapiTime to help to determine the WCET in systems that use them.

DO-178C webinars

DO178C webinars

White papers

Mitigation of interference in multicore processors for A(M)C 20-193
Sysgo WP Developing DO-178C and ED-12C-certifiable multicore software
DO178C Handbook Efficient Verification Through the DO-178C Life Cycle
A Commercial Solution for Safety-Critical Multicore Timing Analysis

Related blog posts

Measuring response times and more with RapiTime

.
2023-03-10

Out of the box RVS integration for DDC-I's Deos RTOS

.
2020-02-23

WCET analysis of object code with zero instrumentation

.
2017-02-27

What happened first? Handling timer wraparound

.
2016-01-08

Pagination

  • Current page 1
  • Page 2
  • Page 3
  • Page 4
  • Page 5
  • Page 6
  • Page 7
  • Page 8
  • Page 9
  • Next page Next ›
  • Last page Last »
  • Solutions
    • Rapita Verification Suite
    • RapiTest
    • RapiCover
    • RapiTime
    • RapiTask
    • MACH178

    • Verification and Validation Services
    • Qualification
    • Training
    • Integration
  • Latest
  • Latest menu

    • News
    • Blog
    • Events
    • Videos
  • Downloads
  • Downloads menu

    • Brochures
    • Webinars
    • White Papers
    • Case Studies
    • Product briefs
    • Technical notes
    • Software licensing
  • Company
  • Company menu

    • About Rapita
    • Careers
    • Customers
    • Distributors
    • Industries
    • Locations
    • Partners
    • Research projects
    • Contact
  • Discover
    • Multicore Timing Analysis
    • Embedded Software Testing Tools
    • Worst Case Execution Time
    • WCET Tools
    • Code coverage for Ada, C & C++
    • MC/DC Coverage
    • Verifying additional code for DO-178C
    • Timing analysis (WCET) & Code coverage for MATLAB® Simulink®
    • Data Coupling & Control Coupling
    • Aerospace Software Testing
    • Automotive Software Testing
    • Certifying eVTOL
    • DO-178C
    • AC 20-193 and AMC 20-193
    • ISO 26262
    • What is CAST-32A?

All materials © Rapita Systems Ltd. 2025 - All rights reserved | Privacy information | Trademark notice Subscribe to our newsletter