This document discusses four approaches to improving Linux performance in embedded multicore devices: 1) the Linux PREEMPT_RT patch set, which replaces kernel spinlocks with mutexes to improve real-time responsiveness but can reduce throughput; 2) LWRT, which partitions Linux into real-time and non-real-time domains to avoid using the kernel and improves both real-time performance and throughput; 3) the Open Event Machine, which partitions Linux and runs some processes on a non-Linux runtime; and 4) hypervisors or "thin kernels", which add a real-time kernel underneath Linux. The document focuses on explaining LWRT and how it compares to PREEMPT_RT in improving both real
RTLinux is a real-time operating system that allows real-time applications to run on top of Linux. It modifies the Linux kernel to add a virtual machine layer with a separate task scheduler that prioritizes real-time tasks over standard Linux processes. This enables RTLinux to support hard real-time deadlines. Programming in RTLinux involves creating modules that can be loaded and unloaded from the kernel using specific commands. Real-time threads and synchronization objects like mutexes are implemented using POSIX interfaces.
This document summarizes key aspects of real-time kernels. It begins by defining a kernel and its role. It then discusses the structure of a real-time kernel, including layers, states, data structures, and primitives. Scheduling mechanisms like ready queues, insertion, and extraction are covered. Task management, semaphores, and intertask communication using mailboxes and cyclical asynchronous buffers are summarized. The document also discusses system overhead considerations like context switching and interrupts.
VxWorks is a real-time operating system developed by Wind River Systems that supports ARM, Intel, and other popular processor architectures. It provides a multitasking environment, virtual memory management, networking capabilities, and powerful development tools. VxWorks uses a client-server microkernel architecture and is highly configurable, allowing it to scale from small embedded systems to large networks. It prioritizes real-time deterministic performance and has found widespread use in avionics, medical devices, industrial automation, and other applications.
This slides indicate an introduction on the definition of real time and RTOSes, then you can find information on introducing RT Linux approaches and comparing them with each other, then finally you can see a latency measurement test done by "Linutronix" in the slides
This document discusses the challenges of real-time computing on Linux and potential solutions. Real-time means very low maximum latency, below 100 microseconds. While Linux was not designed for real-time, it is now used in many embedded systems. Options to address real-time include using separate hardware, a hypervisor with an real-time operating system (RTOS), asymmetric multiprocessing (AMP) with an RTOS, or solutions within Linux like PREEMPT_RT that adds preemption and CPU isolation techniques to reduce worst-case latency without changing applications. The document reviews these approaches and notes that real-time remains an important area as Linux is increasingly used in embedded systems.
The document discusses real-time operating systems for networked embedded systems. It provides an example of a fire alarm system using sensors, controllers and a central server connected by low-bandwidth radio links. It then discusses the need for a collaborative action routing solution that is dynamic, auto-configurable and minimizes collisions. The document outlines features of real-time operating systems including scheduling, resource allocation, interrupt handling and targeting various processor architectures.
The document discusses real-time operating systems for embedded systems. It describes that RTOS are necessary for systems with scheduling of multiple processes and devices. An RTOS kernel manages tasks, inter-task communication, memory allocation, timers and I/O devices. The document provides examples of creating tasks to blink an LED and print to USART ports, using a semaphore for synchronization between tasks. The tasks are run and output is seen on a Minicom terminal.
Real-Time Operating System (RTOS) Vs. General Purpose OS (GPOS)
Can Linux provide real-time guarantees?
Commercial RTOSs
RTLinux Vs. Linux: Architectural comparison
RTLinux Vs. Linux: Code perspective
Get the RTLinux setup ready
Things to Issue and Handling the hard disk
Lab #1: Detailed discussion
RTLinux is a real-time operating system that allows real-time applications to run on top of Linux. It modifies the Linux kernel to add a virtual machine layer with a separate task scheduler that prioritizes real-time tasks over standard Linux processes. This enables RTLinux to support hard real-time deadlines. Programming in RTLinux involves creating modules that can be loaded and unloaded from the kernel using specific commands. Real-time threads and synchronization objects like mutexes are implemented using POSIX interfaces.
This document summarizes key aspects of real-time kernels. It begins by defining a kernel and its role. It then discusses the structure of a real-time kernel, including layers, states, data structures, and primitives. Scheduling mechanisms like ready queues, insertion, and extraction are covered. Task management, semaphores, and intertask communication using mailboxes and cyclical asynchronous buffers are summarized. The document also discusses system overhead considerations like context switching and interrupts.
VxWorks is a real-time operating system developed by Wind River Systems that supports ARM, Intel, and other popular processor architectures. It provides a multitasking environment, virtual memory management, networking capabilities, and powerful development tools. VxWorks uses a client-server microkernel architecture and is highly configurable, allowing it to scale from small embedded systems to large networks. It prioritizes real-time deterministic performance and has found widespread use in avionics, medical devices, industrial automation, and other applications.
This slides indicate an introduction on the definition of real time and RTOSes, then you can find information on introducing RT Linux approaches and comparing them with each other, then finally you can see a latency measurement test done by "Linutronix" in the slides
This document discusses the challenges of real-time computing on Linux and potential solutions. Real-time means very low maximum latency, below 100 microseconds. While Linux was not designed for real-time, it is now used in many embedded systems. Options to address real-time include using separate hardware, a hypervisor with an real-time operating system (RTOS), asymmetric multiprocessing (AMP) with an RTOS, or solutions within Linux like PREEMPT_RT that adds preemption and CPU isolation techniques to reduce worst-case latency without changing applications. The document reviews these approaches and notes that real-time remains an important area as Linux is increasingly used in embedded systems.
The document discusses real-time operating systems for networked embedded systems. It provides an example of a fire alarm system using sensors, controllers and a central server connected by low-bandwidth radio links. It then discusses the need for a collaborative action routing solution that is dynamic, auto-configurable and minimizes collisions. The document outlines features of real-time operating systems including scheduling, resource allocation, interrupt handling and targeting various processor architectures.
The document discusses real-time operating systems for embedded systems. It describes that RTOS are necessary for systems with scheduling of multiple processes and devices. An RTOS kernel manages tasks, inter-task communication, memory allocation, timers and I/O devices. The document provides examples of creating tasks to blink an LED and print to USART ports, using a semaphore for synchronization between tasks. The tasks are run and output is seen on a Minicom terminal.
Real-Time Operating System (RTOS) Vs. General Purpose OS (GPOS)
Can Linux provide real-time guarantees?
Commercial RTOSs
RTLinux Vs. Linux: Architectural comparison
RTLinux Vs. Linux: Code perspective
Get the RTLinux setup ready
Things to Issue and Handling the hard disk
Lab #1: Detailed discussion
Introduction to BeRTOS, real time embedded operating system open source. BeRTOS is free also for commercial projects or closed source applications.
http://www.bertos.org/download/
How to Measure RTOS Performance – Colin Walls
In the world of smart phones and tablet PCs memory might be cheap, but in the more constrained universe of deeply embedded devices, it is still a precious resource. This is one of the many reasons why most 16- and 32-bit embedded designs rely on the services of a scalable real-time operating system (RTOS). An RTOS allows product designers to focus on the added value of their solution while delegating efficient resource (memory, peripheral, etc.) management. In addition to footprint advantages, an RTOS operates with a degree of determinism that is an essential requirement for a variety of embedded applications. This paper takes a look at “typical” reported performance metrics for an RTOS in the embedded industry.
The survey on real time operating systems (1)manojkumarsmks
This document discusses real-time operating systems (RTOS) for small microcontrollers and various examples. It covers topics like RTOS architecture, language support, services provided through APIs, and technical support needs. Examples discussed include uITRON and TOPPERS/FDMP RTOS specifications, MARUTI which is a hard real-time system, and eRTOS designed for wearable computers. The document compares different RTOS and concludes that RTOS have increasingly been used in small microcontrollers to enable software optimization, distribution, and synchronization.
The document provides an introduction to operating systems and real-time operating systems (RTOS). It defines an operating system as software that manages computer resources and provides common services for programs. An RTOS is designed for systems where response time is critical. The document discusses the components, features and types of both operating systems and RTOS, including examples like VxWorks and QNX.
This document discusses real-time operating systems (RTOS). An RTOS is a data processing system that can process inputs and respond within a small time interval. It ensures tasks are completed within a specified time delay by responding quickly to inputs. RTOS enable multitasking and prioritized process threads. They see widespread use in modern telecommunications, military operations, radar systems, and more. RTOS are either hard real-time systems that guarantee critical tasks finish on time with no virtual memory, or soft real-time systems that prioritize critical tasks over others but are less restrictive and not catastrophic if deadlines are missed.
This document provides an introduction to real-time systems and discusses approaches to making Linux a real-time operating system. It defines hard and soft real-time systems and explains why Linux is commonly used instead of dedicated real-time operating systems. The document then discusses two main solutions, PREEMPT_RT and Xenomai 3, which provide patches to make Linux meet timing constraints through different approaches. It also provides an overview of basic real-time concepts like scheduling algorithms, preemptive vs. non-preemptive scheduling, and interprocess communication.
This document discusses real-time operating systems (RTOS), focusing on principles and a case study of EMERALDS, an RTOS designed for small memory embedded systems. It describes the requirements and classifications of RTOSs, approaches to minimizing code size and execution overhead in EMERALDS, and how EMERALDS implements efficient real-time scheduling, semaphores, message passing and memory protection for constrained embedded devices. The document also discusses how EMERALDS was adapted to the OSEK standard for automotive systems.
This document provides an overview of real-time operating systems (RTOS), including their key characteristics, scheduling approaches, and commercial examples. RTOS are used in applications that require tasks to complete work and deliver services on time. They use priority-based and clock-driven scheduling algorithms like rate monotonic analysis and earliest deadline first to ensure real-time constraints are met. Commercial RTOS aim to provide features like priority levels, fast task preemption, and predictable interrupt handling for real-time applications.
DPDK Summit - 08 Sept 2014 - Intel - Networking Workloads on Intel ArchitectureJim St. Leger
Venky Venkatesan presents information on the Data Plane Development Kit (DPDK) including an overview, background, methodology, and future direction and developments.
QNX is a real-time operating system developed by QNX Software Systems. It is based on the Neutrino microkernel. QNX is used in industrial, network, telecommunications, medical, and automotive devices where predictable and reliable performance is critical. Some key applications of QNX include power grids, emergency response systems, vehicle infotainment systems, traffic control, and industrial automation.
Real Time Operating system (RTOS) - Embedded systemsHariharan Ganesan
A real-time operating system (RTOS) is an operating system designed for embedded systems where responses need to occur within strict time constraints. An RTOS prioritizes tasks and responds immediately to inputs. There are two types - hard RTOS which must meet deadlines to avoid catastrophic failure, and soft RTOS where occasionally missing deadlines does not cause failure. An RTOS manages tasks, schedules tasks and system resources, and handles interrupts to ensure time-critical applications perform as required.
VxWorks is a real-time operating system (RTOS) that is commonly used in applications that have strict timing requirements. It provides features like multitasking, scheduling, interrupt handling, intertask communication methods like shared memory, message queues, and semaphores. VxWorks uses a layered architecture with a microkernel at its core to provide functions like multiprocessing and POSIX compatibility. It is well-suited for applications in fields like avionics, medical devices, industrial automation, and more where deterministic behavior is important.
This document discusses the basic functions and types of real-time operating systems (RTOS) for embedded systems. It describes key RTOS functions like integrated development environments, timers, scheduling, device drivers, inter-process communication, and memory management. It also categorizes different types of RTOS as in-house developed, broad-based commercial, general purpose OS with RTOS features, and special focus RTOS tailored for specific processors. Overall, the document provides a high-level overview of RTOS functions and classifications.
The document discusses real-time operating systems (RTOS). It defines an RTOS as an OS intended to serve real-time application requests. It classifies RTOS as hard, firm, or soft based on adherence to deadlines. It describes RTOS architecture including tasks, synchronization, communication, memory management, and other kernel functions. It lists features such as multithreading, priorities, communication, and short latencies. Finally, it provides examples of widely used RTOS like QNX, RTLinux, VxWorks, and Windows CE.
Microsoft's Production Configurable Cloud leverages FPGAs and a programmable infrastructure to provide accelerated computing capabilities. Key aspects include:
- Using FPGAs on servers and smartNICs to accelerate networking, storage, security and other functions through reconfigurable hardware.
- Developing a pod architecture that connects multiple FPGAs within a rack for low-latency sharing of resources.
- Creating a programmable "configurable cloud" infrastructure that allows workloads to be accelerated locally, through infrastructure enhancements, or remotely on other servers' FPGAs.
- Early FPGA applications provided significant query latency and throughput improvements for Bing search functions. The approach is now used broadly in
The document discusses a fire alarm system that uses a centralized server connected to various sensors and controllers via low bandwidth radio links. It proposes using a collaborative routing approach with dynamic and auto-configurable routing to minimize collisions and reduce the number of intermediate nodes, providing fast response times and secure communication. It also discusses using ARM-based controllers to connect to microcontroller-based sensors.
This document discusses real-time operating system (RTOS) concepts. It defines real-time as responsiveness defined by external processes. An RTOS guarantees tasks will finish within time constraints. It explains characteristics like preemptive multitasking, prioritized processes, interrupt handling. The document also covers RTOS scheduling, dispatching, time specifications for tasks and interrupts. Common real-time applications are also listed like military, telecommunications, aviation and more.
This document discusses three approaches to enabling real-time capabilities in Linux:
1) The PREEMPT_RT kernel patch, which modifies Linux to allow full preemption and reduce jitter through priority inheritance. This adds some overhead.
2) User space partitioning, which isolates CPU cores to run single POSIX threads without kernel interference, enabling very low overhead handling of events.
3) Dual-OS partitioning, which runs a real-time executive on isolated CPU cores entirely separate from the Linux kernel for maximum determinism and minimal latency. Each approach provides different performance, latency, and functionality trade-offs.
This document discusses real time operating systems for networked embedded systems. It provides an example of a fire alarm system with hundreds of sensors communicating over low bandwidth radio links to controllers and a central server. It outlines the challenges in ensuring sensor information is logged and appropriate action initiated in real time. The document then discusses real time operating systems, including scheduling algorithms like priority scheduling and clock driven scheduling. It covers features of RTOS like interrupt handling and resource allocation. Finally, it mentions specific RTOS like Linux, RTLinux, and the author's own rtker RTOS.
Introduction to BeRTOS, real time embedded operating system open source. BeRTOS is free also for commercial projects or closed source applications.
http://www.bertos.org/download/
How to Measure RTOS Performance – Colin Walls
In the world of smart phones and tablet PCs memory might be cheap, but in the more constrained universe of deeply embedded devices, it is still a precious resource. This is one of the many reasons why most 16- and 32-bit embedded designs rely on the services of a scalable real-time operating system (RTOS). An RTOS allows product designers to focus on the added value of their solution while delegating efficient resource (memory, peripheral, etc.) management. In addition to footprint advantages, an RTOS operates with a degree of determinism that is an essential requirement for a variety of embedded applications. This paper takes a look at “typical” reported performance metrics for an RTOS in the embedded industry.
The survey on real time operating systems (1)manojkumarsmks
This document discusses real-time operating systems (RTOS) for small microcontrollers and various examples. It covers topics like RTOS architecture, language support, services provided through APIs, and technical support needs. Examples discussed include uITRON and TOPPERS/FDMP RTOS specifications, MARUTI which is a hard real-time system, and eRTOS designed for wearable computers. The document compares different RTOS and concludes that RTOS have increasingly been used in small microcontrollers to enable software optimization, distribution, and synchronization.
The document provides an introduction to operating systems and real-time operating systems (RTOS). It defines an operating system as software that manages computer resources and provides common services for programs. An RTOS is designed for systems where response time is critical. The document discusses the components, features and types of both operating systems and RTOS, including examples like VxWorks and QNX.
This document discusses real-time operating systems (RTOS). An RTOS is a data processing system that can process inputs and respond within a small time interval. It ensures tasks are completed within a specified time delay by responding quickly to inputs. RTOS enable multitasking and prioritized process threads. They see widespread use in modern telecommunications, military operations, radar systems, and more. RTOS are either hard real-time systems that guarantee critical tasks finish on time with no virtual memory, or soft real-time systems that prioritize critical tasks over others but are less restrictive and not catastrophic if deadlines are missed.
This document provides an introduction to real-time systems and discusses approaches to making Linux a real-time operating system. It defines hard and soft real-time systems and explains why Linux is commonly used instead of dedicated real-time operating systems. The document then discusses two main solutions, PREEMPT_RT and Xenomai 3, which provide patches to make Linux meet timing constraints through different approaches. It also provides an overview of basic real-time concepts like scheduling algorithms, preemptive vs. non-preemptive scheduling, and interprocess communication.
This document discusses real-time operating systems (RTOS), focusing on principles and a case study of EMERALDS, an RTOS designed for small memory embedded systems. It describes the requirements and classifications of RTOSs, approaches to minimizing code size and execution overhead in EMERALDS, and how EMERALDS implements efficient real-time scheduling, semaphores, message passing and memory protection for constrained embedded devices. The document also discusses how EMERALDS was adapted to the OSEK standard for automotive systems.
This document provides an overview of real-time operating systems (RTOS), including their key characteristics, scheduling approaches, and commercial examples. RTOS are used in applications that require tasks to complete work and deliver services on time. They use priority-based and clock-driven scheduling algorithms like rate monotonic analysis and earliest deadline first to ensure real-time constraints are met. Commercial RTOS aim to provide features like priority levels, fast task preemption, and predictable interrupt handling for real-time applications.
DPDK Summit - 08 Sept 2014 - Intel - Networking Workloads on Intel ArchitectureJim St. Leger
Venky Venkatesan presents information on the Data Plane Development Kit (DPDK) including an overview, background, methodology, and future direction and developments.
QNX is a real-time operating system developed by QNX Software Systems. It is based on the Neutrino microkernel. QNX is used in industrial, network, telecommunications, medical, and automotive devices where predictable and reliable performance is critical. Some key applications of QNX include power grids, emergency response systems, vehicle infotainment systems, traffic control, and industrial automation.
Real Time Operating system (RTOS) - Embedded systemsHariharan Ganesan
A real-time operating system (RTOS) is an operating system designed for embedded systems where responses need to occur within strict time constraints. An RTOS prioritizes tasks and responds immediately to inputs. There are two types - hard RTOS which must meet deadlines to avoid catastrophic failure, and soft RTOS where occasionally missing deadlines does not cause failure. An RTOS manages tasks, schedules tasks and system resources, and handles interrupts to ensure time-critical applications perform as required.
VxWorks is a real-time operating system (RTOS) that is commonly used in applications that have strict timing requirements. It provides features like multitasking, scheduling, interrupt handling, intertask communication methods like shared memory, message queues, and semaphores. VxWorks uses a layered architecture with a microkernel at its core to provide functions like multiprocessing and POSIX compatibility. It is well-suited for applications in fields like avionics, medical devices, industrial automation, and more where deterministic behavior is important.
This document discusses the basic functions and types of real-time operating systems (RTOS) for embedded systems. It describes key RTOS functions like integrated development environments, timers, scheduling, device drivers, inter-process communication, and memory management. It also categorizes different types of RTOS as in-house developed, broad-based commercial, general purpose OS with RTOS features, and special focus RTOS tailored for specific processors. Overall, the document provides a high-level overview of RTOS functions and classifications.
The document discusses real-time operating systems (RTOS). It defines an RTOS as an OS intended to serve real-time application requests. It classifies RTOS as hard, firm, or soft based on adherence to deadlines. It describes RTOS architecture including tasks, synchronization, communication, memory management, and other kernel functions. It lists features such as multithreading, priorities, communication, and short latencies. Finally, it provides examples of widely used RTOS like QNX, RTLinux, VxWorks, and Windows CE.
Microsoft's Production Configurable Cloud leverages FPGAs and a programmable infrastructure to provide accelerated computing capabilities. Key aspects include:
- Using FPGAs on servers and smartNICs to accelerate networking, storage, security and other functions through reconfigurable hardware.
- Developing a pod architecture that connects multiple FPGAs within a rack for low-latency sharing of resources.
- Creating a programmable "configurable cloud" infrastructure that allows workloads to be accelerated locally, through infrastructure enhancements, or remotely on other servers' FPGAs.
- Early FPGA applications provided significant query latency and throughput improvements for Bing search functions. The approach is now used broadly in
The document discusses a fire alarm system that uses a centralized server connected to various sensors and controllers via low bandwidth radio links. It proposes using a collaborative routing approach with dynamic and auto-configurable routing to minimize collisions and reduce the number of intermediate nodes, providing fast response times and secure communication. It also discusses using ARM-based controllers to connect to microcontroller-based sensors.
This document discusses real-time operating system (RTOS) concepts. It defines real-time as responsiveness defined by external processes. An RTOS guarantees tasks will finish within time constraints. It explains characteristics like preemptive multitasking, prioritized processes, interrupt handling. The document also covers RTOS scheduling, dispatching, time specifications for tasks and interrupts. Common real-time applications are also listed like military, telecommunications, aviation and more.
This document discusses three approaches to enabling real-time capabilities in Linux:
1) The PREEMPT_RT kernel patch, which modifies Linux to allow full preemption and reduce jitter through priority inheritance. This adds some overhead.
2) User space partitioning, which isolates CPU cores to run single POSIX threads without kernel interference, enabling very low overhead handling of events.
3) Dual-OS partitioning, which runs a real-time executive on isolated CPU cores entirely separate from the Linux kernel for maximum determinism and minimal latency. Each approach provides different performance, latency, and functionality trade-offs.
This document discusses real time operating systems for networked embedded systems. It provides an example of a fire alarm system with hundreds of sensors communicating over low bandwidth radio links to controllers and a central server. It outlines the challenges in ensuring sensor information is logged and appropriate action initiated in real time. The document then discusses real time operating systems, including scheduling algorithms like priority scheduling and clock driven scheduling. It covers features of RTOS like interrupt handling and resource allocation. Finally, it mentions specific RTOS like Linux, RTLinux, and the author's own rtker RTOS.
Testing real-time Linux. What to test and how Chirag Jog
The document discusses testing of the real-time Linux kernel. It explains that real-time kernel testing focuses on functionality, performance, and latency. Key aspects to test include signal delivery latency, scheduling jitter, and context switch duration. Proper hardware setup and kernel configuration are important. Test cases should run as real-time processes and avoid page faults, disk I/O, and other sources of unpredictable latency when measuring real-time performance.
This document provides an introduction to using the RTX real-time operating system with the Keil uVision IDE. It describes how to create a basic RTX application with multiple tasks and use RTX functions for task scheduling and synchronization. The document gives an example 4-task application that blinks LEDs, increments counters, and displays text. It also discusses using semaphores, specifically mutexes, to control access to shared resources between tasks in a real-time system.
The document discusses the Open Data Plane (ODP) project, which aims to create an open source framework for data plane applications. ODP provides a standardized API to enable networking applications across different architectures like ARM, Intel and PowerPC. It is based on the Event Machine model of work-driven processing. ODP implementations optimize the API for different hardware platforms while providing application portability. The project aims to support functions like dynamic load balancing, power management, and virtual switch integration.
This document discusses real-time operating systems (RTOS) and provides case studies of several common RTOS. It begins by defining real-time and describing the characteristics of soft and hard real-time systems. The key components of an RTOS are then outlined. Examples of commercial RTOS like VxWorks and open source RTOS like RTLinux, RTAI, and FreeRTOS are provided. More detailed case studies of RTLinux, RTAI, MicroC/OSII, VxWorks, eCos, and TinyOS follow, describing their features, uses, and differences.
The document provides an overview of microcontrollers and embedded systems. It defines an embedded system and describes their characteristics such as real-time operation, small size, low power usage, and operation in harsh environments. It discusses the hardware components of typical embedded systems including microcontrollers. It then focuses on the 8051 microcontroller, describing its architecture and pin layout.
The document discusses embedded systems and microcontrollers. It defines an embedded system as a combination of computer hardware and software designed for a specific application. Microcontrollers are similar to microprocessors but have memory and I/O integrated on a single chip, making them well-suited for embedded applications that require low cost, low power consumption, and small size. The 8051 microcontroller is commonly used in embedded systems due to its low price and availability of development tools. Programming techniques for microcontrollers include assembly language and high-level languages like C.
This document discusses real-time operating systems (RTOS). It begins by defining an RTOS and distinguishing it from traditional operating systems by its ability to respond to external events in a timely manner. It describes the different types of RTOS based on timing constraints. It then covers key RTOS concepts like preemptive priority scheduling, multitasking, inter-task communication, priority inheritance, and memory management. The document also discusses the Nucleus RTOS and whether RTOS will replace traditional operating systems.
Marcelo Perazolo, Lead Software Architect, IBM Corporation - Monitoring a Pow...Nagios
Marcelo Perazolo, Lead Software Architect, IBM Corporation - In this session, Marcelo will describe how Nagios can be
integrated and extended for the monitoring of a typical
power-based converged infrastructure, and how it interfaces with existing element managers to provide a single point of integration for passive and active monitoring purposes.
An operating system is software that manages computer resources and provides services to application programs. It sits between the computer hardware and application software. There are three main types of operating systems: stand-alone, network, and embedded. Real-time operating systems (RTOS) are designed for applications with time-critical deadlines like process control. Key features of an RTOS include short and predictable context switching, interrupt handling times, and inter-process communication. Popular RTOS include VxWorks, QNX, and RTLinux.
Tommaso Cucinotta - Low-latency and power-efficient audio applications on Linuxlinuxlab_conf
Building Linux-based low-latency audio processing software for nowadays multi-core devices can be cumbersome. I’ll present some of our on-going research on the topic at the Real-Time Systems Lab of Scuola Superiore Sant’Anna, focusing on sound synthesis on Android where power-efficiency is a must.
The talk will provide basic background information on how the audio sub-system of Linux works, in terms of interactions between the Linux kernel and the ALSA sound architecture, including how user-space applications normally cope with low-latency requirements, touching briefly on design concepts behind the existence of the JACK low-latency framework. Then, a few concepts will be provided on the peculiarities of the Android audio processing pipeline, crossing the concepts with the due complications arising from the world of mobile and power-efficient devices. Throughout the talk, I’ll touch upon concepts behind our research efforts on the topic, describing how properly designed real-time CPU scheduling strategies can make a difference in what is achievable in this area.
An operating system controls computer resources and provides a platform for applications. It sits between hardware like the CPU, memory, and I/O devices, and software like compilers, databases, and word processors. There are three main types of operating systems: stand-alone systems for desktops, network systems for servers, and embedded systems found in devices. A real-time operating system (RTOS) is designed for applications with time-critical deadlines like process and thread execution times. An RTOS has features like short and predictable context switching, interrupt handling times, and inter-process communication mechanisms. Popular RTOSs include LynxOS, QNX, RTLinux, and VxWorks.
The document discusses network design concepts for building a resilient network. It emphasizes the importance of considering redundancy at multiple levels, from the physical infrastructure to network protocols. Well-designed networks are modular, have clearly defined functional layers, and incorporate redundancy through techniques like load balancing and diverse circuit paths. Hierarchical network designs with logical areas can also improve convergence times during failures.
The document discusses embedded computing systems and outlines some key points:
- Embedded systems are part of larger systems that perform specific functions in constrained, reactive environments using a combination of hardware and software.
- They have real-time requirements and challenges include high complexity, distributed networks, and meeting deadlines with increasing functionality.
- Embedded systems come in many forms, from automotive and industrial control systems to wireless sensor networks and systems within the human body.
F9 is a new open source microkernel designed for deeply embedded systems like IoT devices. It aims to provide efficiency, security, and a flexible development environment. F9 follows microkernel principles with minimal kernel functionality and isolates components as user-level processes. It uses capabilities for access control and focuses on performance through techniques like tickless scheduling and adaptive power management.
This document provides an introduction and overview of embedded systems and embedded system design. It discusses the following key points in 3 sentences:
1. It defines embedded systems and lists their essential components as well as characteristics including low cost, low power usage, and small size.
2. It discusses the requirements of embedded microcontroller cores including memory, ports, timers, interrupts, and serial data transfer standards to interface with real-world peripherals.
3. It also covers embedded programming, real-time operating systems, example applications, and textbooks on embedded systems design.
Embedded systems are computer systems designed to perform dedicated functions in devices. They use microprocessors or microcontrollers and are optimized for their specific tasks. Embedded systems control many common devices today like phones, routers, vehicles, and medical equipment. They range from simple systems with no interface to complex systems with graphical user interfaces. Common processor architectures include ARM, MIPS, PowerPC, x86 and others. Embedded software uses various architectures from simple control loops to preemptive multitasking with real-time operating systems.
Webinar: OpenEBS - Still Free and now FASTEST Kubernetes storageMayaData Inc
Webinar Session - https://youtu.be/_5MfGMf8PG4
In this webinar, we share how the Container Attached Storage pattern makes performance tuning more tractable, by giving each workload its own storage system, thereby decreasing the variables needed to understand and tune performance.
We then introduce MayaStor, a breakthrough in the use of containers and Kubernetes as a data plane. MayaStor is the first containerized data engine available that delivers near the theoretical maximum performance of underlying systems. MayaStor performance scales with the underlying hardware and has been shown, for example, to deliver in excess of 10 million IOPS in a particular environment.
This document provides an introduction to high-performance computing (HPC) including definitions, applications, hardware, and software. It defines HPC as utilizing parallel processing through computer clusters and supercomputers to solve complex modeling problems. The document then describes typical HPC cluster hardware such as computing nodes, a head node, switches, storage, and a KVM. It also outlines cluster management software, job scheduling, and parallel programming tools like MPI that allow programs to run simultaneously on multiple processors. An example HPC cluster at SIU called Maxwell is presented with its technical specifications and a tutorial on logging into and running simple MPI programs on the system.
Similar to Four Ways to Improve Linux Performance IEEE Webinar, R2.0 (20)
Four Ways to Improve Linux Performance IEEE Webinar, R2.0
1. 4 Ways to Improve Linux Performance
Michael Christofferson
Director Product Marketing, Enea
IEEE/Enea Webinar
July 23, 2013
2. FOUNDED
1968
TEN OFFICES
IN NORTH
AMERICA,
EUROPE AND
ASIA
REVENUE
67M
USD
NO. OF
EMPLOYEES
426
Increasing data traffic in communication devices
require new and innovative software solutions to
handle bandwidth, performance and power
requirements.
Enea software is heavily used in wireless
Infrastructure (Macro, small cell), gateway,
terminal, military, auto, etc.
More than 250M of the 325M LTE population
coverage is powered by Enea Solutions
Enea Solutions run in more than 50% of the
world’s 8.2M radio base stations.
Enea has recently released its first commercial
Linux distribution, built by Yocto, and specially
tailored for networking and communications
Global presence, global development, and
headquartered in Stockholm, Sweden
Enea - Powering Communications
Numbers for 2011
3. FOUNDED
1968
Overview of four approaches to enhancement of standard Linux
performance in embedded multicore devices.
Linux PREEMPT_RT CONFIG Patch Set
Enea LWRT
Open Event Machine
Hypervisors or “thin kernel” solutions
Relative performance comparisons, as well as other metrics
that reflect “Pros and Cons” of each approach
Agenda
4. Many measures of “performance”
•Real-time Responsiveness
– In embedded, often linked with the concept of “deterministic” response
– But not always!! …. See next slide
•Throughput
– Discreet event processing bandwidth or rates
– Does not necessarily mean short or even deterministic real-time response
•High Performance Computing
– Massive compute intensive applications like modeling and simulation, and mathematical
related computations
– Not the same as throughput
What Does Performance Mean?
=> For embedded, it’s about Real-time response and Throughput
5. • Real-time systems
– Have “operational deadlines from event to system response”
– Must guarantee the response to external events within strict time constraints
• Non-real-time systems
– Cannot guarantee response time in any situation
– Are often optimized for best-effort, high throughput performance
• “Real-time response” means deterministic response
– Can mean seconds, milliseconds, microseconds.
– I.e. not necessarily short times, but usually this is the case
• Real-time system classifications:
– Hard: missing a deadline means total system failure
– Firm: infrequent misses are tolerable, but result is useless. QoS degrades quickly
– Soft: infrequent misses are tolerable, increased frequency degrades QoS more slowly
=> Real-time performance OFTEN is contradictory to Throughput!!
What Does “Real-time” Performance Mean?
6. Examples of real-time systems
• Hard real-time applications:
– Automotive: anti-lock brakes, car engine control
– Medical: heart pacemakers
– Industrial: process controllers, robot control
Throughput NOT an issue
• Firm real-time applications:
– 3G/4G baseband processing/signaling in base stations and radio network
controllers
– 3G/4G baseband processing/signaling in wireless modems (phones, tablets)
– Many other examples in the networking space – RRU, optical transport,
backhaul, too numerous to list
Throughput is often an issue
• Soft real-time applications:
– IP network control signaling, network servers
– Live audio-video systems on the edge or in data centers
Throughput with “good enough” real time response IS the issue
7. Four Ways for Better Performance in Linux:
Linux KernelLinux Kernel
Vertically partition Linux
in two domains:
Linux KernelLinux Kernel Linux KernelLinux Kernel
Add a thin real-time
kernel underneath Linux:
Rework the internals of
Linux:
Realtime KernelRealtime Kernel
RT Runtime- LWRTRT Runtime- LWRT
The PREEMPT_RT
patch
“Thin-kernel” or
virtualization
Vertical Partitioning +
User mode Runtime
RT appsRT apps
Event Machine
Partition Linux in two
domains:, one not
running Linux at all
Linux KernelLinux Kernel
Event MachineEvent Machine
9. What Problem is PREEMPT_RT Trying to Solve?
Minimize Linux Interrupt Processing
Delays from external event to response
External
Interrupt
Triggered
Interrupt
Taken
Interrupt
Received in
User/Thread
Context
Critical section
with interrupts
disabled
HW
Exception
“Top Half” / ISR Exit from IRQ Reschedule Context Switch
Something else is
executing
(probably
another ISR)
E.g. locks (xtime lock could
be one example?)
Softirqs, RCUs Priority
inversion/
conflict
Cache misses, etc.
Signal/
Wakeup
Locks,
RCUs, etc.
Resource Conflicts
10. The CONFIG_PREEMPT_RT patch set
• Started 10+ years ago
– Before multicore evolution; uni-core optimized technology
– Many other contributors since then
• Replaces most kernel spinlocks with mutexes with priority
inheritance
• Moves most interrupt handling to kernel threads
– This means many drivers must be modified
• Roughly, PREEMPT_RT patches 500+ locations in the
kernel, with 11,500+ new lines of code in total.
• In a multicore device, is “system wide in scope”
Improves real-time performance (interrupt latency)
but AT THE EXPENSE of throughput
11. PREEMPT_RT Throughput/RT Tradeoff
A Very Simple Example
Linux 3.6.4:
# netperf -H localhost -t TCP_STREAM -A 16K,16K -l 120 -C -D 20
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % U % S us/KB us/KB
87380 16384 16384 120.00 8782.10 -1.00 84.81 -1.000 1.582
Linux 3.6.4-rt10 (PREEMPT_RT):
# netperf -H localhost -t TCP_STREAM -A 16K,16K -l 120 -C -D 20
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % U % S us/KB us/KB
87380 16384 16384 120.00 4185.48 -1.00 70.21 -1.000 2.748
But this is a simple example that doesn’t always apply
12. Other CONFIG_PREEMPT_RT Characteristics
• ALL Linux Solution
– API’s / programming paradigm
– Including all tools
– BUT!! Requires driver modifications for all drivers
• Compatible with Core Isolation/Shielding techniques
– Can work reasonably well for both real-time and throughput in a
“bare metal” environment, i.e. no multithreading on isolated cores
• Linux SMP style load balancing, for what it’s worth
• Standard Linux memory protection
• Standard Linux Power Management
14. LWRT and the Vertical Partitioning Concept
• Partitioning of the system into
separate real-time critical
(shielded cores) an non-critical
domains.
• It is often the Linux kernel itself
that introduces real-time
problems.
• Real-time partition does not need
full POSIX/Linux API
• A combination of partitioning,
combined with a user-mode
environment that avoids using the
kernel can improve performance
and real-time characteristics
compared to a standard Linux.
“Improve performance and
realtime characteristics
under Linux by partitioning
the system into logical
domains, and by avoiding
usage of the Linux kernel and
its resources more than
necessary”
15. The LWRT Vertical Partitioning Concept (2)
• Configure processes and interrupts to run with core affinity
• Make minor modifications to the kernel to avoid running
unnecessary kernel threads/timers on real-time cores
• Avoid using/calling the kernel, and rely on a user-mode
execution runtime environment
Use Cases:
a.When targeting interrupt latency at a 3-10 us average
and 15-30 us worst case requirements
b.When the application requires multi-threading
performance
16. How does LWRT work?
PthreadPthread
Core
0
Core
0
Core
N
Core
N
Linux KernelLinux Kernel
PthreadPthread
LWRT EnvironmentLWRT Environment
LWRT Kernel
Module
Realtime ProcessesRealtime ProcessesNon-realtime ProcessesNon-realtime Processes
LWRT partitions the system into one realtime
domain and one non-realtime domain.
LWRT adds a user-mode runtime environment,
including an optimized user-mode scheduler.
LWRT adds a kernel module to catch and forward
interrupts to the user-mode environment.
LWRT migrates some specific kernel functionality
(e.g. timers) away from the realtime domain.
17. What are the benefits of LWRT?
PthreadPthread
Core
0
Core
0
Core
N
Core
N
Linux KernelLinux Kernel
PthreadPthread
LWRT EnvironmentLWRT Environment
LWRT Kernel
Module
Realtime ProcessesRealtime ProcessesNon-realtime ProcessesNon-realtime Processes
LWRT provides a solution that is unencumbered by
GPL, even for interrupt driven code which can be
placed in user-space without any major penalty.
LWRT provides very good (i.e. low-latency) interrupt
response time, all the way up to user-mode.
LWRT provides low latency and high throughput. LWRT
does not depend on the PREEMPT_RT patch, and does
not affect throughput negatively.
LWRT provides optimized APIs for realtime
applications, and allows the same application to use
the POSIX/Linux APIs when realtime doesn’t matter.
LWRT is an “all-Linux” solution, based on a single Linux
Kernel. Thus, almost all tools from the existing Linux
ecosystem will be available.
19. 0
20000
40000
60000
80000
100000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
pthreads
Enea’s User-Space Linux Executive
Much better performance i.e.
lower scheduling latency
Much better real-time characteristics,
i.e. less variance.
Clock cycles
(lower is better)
Number of samples
measured
(ideally a single peak)
Scheduling Latency – LWRT vs Pthreads
22. Throughput ≈ “Idle” Time
Based on a Real-world LTE Example
0 500 μs 1000 μs 2000 μs1500 μs
Cell N
Cell 1
Cell 0
“Idle” Time
In our example:
“Theoretical”
maximum for a
system with
infinitesimally little
overhead is 400 μs
In our example:
“Theoretical”
maximum for a
system with
infinitesimally little
overhead is 400 μs
24. Other LWRT Characteristics
• NOT ALL Linux Solution
– Different API’s, programming paradigm
– Does include all Linux tools, except for LWRT thread awareness
– BUT, doesn’t require standard Linux driver modification
• Depends on Core Isolation/Shielding
• Slightly better real-time response/determinism than
PREEMPT_RT
– Interrupt handling model “cleaner”
• Better than PREEMPT_RT for Throughput
– But only if Multithreading in the application is necessary
– Not for bare metal
• No load balancing – the current vertical partitioning concept
prohibits it
• No memory protection between threading environments on a
core
– Best implementation requires ONE pthread per core
• Not standard Linux Power Management
26. What does Event Machine Look Like?
EMEM
Core
0
Core
0
Core
N
Core
N
Linux KernelLinux Kernel
EMEM EMEM EMEM
EM needs a “dispatcher”EM needs a “dispatcher”
EM Scheduler
Realtime ApplicationsRealtime ApplicationsNon-realtime ProcessesNon-realtime Processes
EM partitions the system into one realtime
domain and one non-realtime domain, like
LWRT.
EM is a run-to-completion model for
individual “contextless” work packages. NO
threading or OS model .
EM does not necessary need a special
interrupt handling model. Needs a “scheduler”
in either Linux partition OR in HW
EM does not require kernel mods, nor core
isolation, but it can use core shielding, i.e.
non-essential Linux processes and
interrupts are migrated away from the EM
cores.
27. Event Machine
• An efficient (low overhead) execution
model for data plane processing.
• An “event” based programming
paradigm, replacing traditional threads
and processes.
– “Events are data associated with code
– Run-to-completion model code. This means
“context-less” or “state-less” code for
processing
• New “first class” OS primitives:
queues, events, execution objects.
– Can work within an RTOS environment!! See
next slide
• A framework for distribution and
scheduling in multicore scenario.
• A standardized API.
• HW offloading friendly API.
EOX
Scheduler
Core/Thread 1
EOX
EOY
Core/Thread N
EOX
EOY
DispatcherDispatcher
28. Push versus Pull Models
• Pull model
– Simple design
– Passive loadbalancing.
– Offload a majority of scheduling decisions
to HW
– Core hot-plug(powersave) easier to
implement.
– Cache cold problems on MIMO/SIMO
queues.
• Push model
– Cache prefetching can be improved.
– Active load balancing protocols needed.
– Offloading scheduling decisions to I/O
co/processor ? i.e. smart HW queues.
• Push/Pull
– Pull whenever HW can schedule I/O.
– Keep it simple.
EOX
Scheduler
Core/Thread 1
EOX
EOY
Core/Thread N
EOX
EOY
DispatcherDispatcher
30. Other Event Machine Characteristics
• NOT ALL Linux Solution
– Different API’s, programming paradigm on EM cores
• This means tools as well
– Requires restructuring code into simple, non-preemptive, run-
to-completion models …. “Context-less” processing
• Depends on Core Isolation/Shielding
• Superior for max data plane THROUGHPUT
• Real-time response is not part of the equation
– Time to process events is not a parameter
– But it “could” result in good real-time response depending on
use case
• Designed for best load balancing on the data plane
• No memory protection EM instances on cores
• Not standard Linux Power Management
– But not a hard problem to solve in a “Pull” model
32. Virtualizes Linux
Examples includes hypervisor, Xenomai, RTLinux etc
Provides a highly deterministic RTOS environment for RT apps
Cannot completely utilize the Linux eco-system (e.g. tools) in the realtime domain.
Suitable for very high real-time requirements, inherited from classic RTOS domains
CPU 0
Multicore SoC
RT OS
CPU 1 CPU 2
Tools
CPU 3 CPU 4 CPU 5
Virtual Machine
Bare Metal OR
RT Apps
Data Plane fast path application
CPU 6 CPU 7
Linux
Real Time Virtualization Solution
33. Hypervisor Characteristics
• NOT ALL Linux Solution
– Different API’s, programming paradigm for real-time
cores
• This means tools as well
• Superior real-time response
• Excellent THROUGHPUT
• Memory protection across cores
But best use case is for legacy migration or
consolidation. Hypervisors really not discussed
too much anymore in the embedded industry
34. Four Ways for Better Performance in Linux:
Linux KernelLinux Kernel
Vertically partition Linux
in two domains:
Linux KernelLinux Kernel Linux KernelLinux Kernel
Add a thin real-time
kernel underneath Linux:
Rework the internals of
Linux:
Realtime KernelRealtime Kernel
RT Runtime- LWRTRT Runtime- LWRT
The PREEMPT_RT
patch
“Thin-kernel” or
virtualization
Vertical Partitioning +
User mode Runtime
RT appsRT apps
Event Machine
Partition Linux in two
domains:, one not
running Linux at all
Linux KernelLinux Kernel
Event MachineEvent Machine
Enea supports PREEMPT_RT, Virtualization, LWRT
Event Machine with Linux is a research topic