Overview

Concurrent’s RedHawk Linux is an industry-standard, real-time version of the open source Linux operating system for Intel and AMD-based systems. RedHawk Linux provides the guaranteed performance needed in time-critical and hard real-time environments. RedHawk is the ideal Linux solution for a broad range of deterministic applications such as modeling, simulation, data acquisition, industrial control and medical imaging systems. RedHawk guarantees that a user-level application can respond to an external event in less than 30 microseconds on a shielded processor.

RedHawk Linux includes all the features of Red Hat Enterprise Linux. The user-level commands, utilities and system administration are compatible with standard Red Hat. RedHawk achieves its superior real-time performance by providing the latest official release from kernel.org that includes key open source patches and kernel enhancements developed by Concurrent. RedHawk user libraries provide access to value-add features that are not part of other Linux offerings. RedHawk is fully compatible with standard Linux userlevel APIs, thus Linux applications written for other Linux distributions will run on RedHawk without modification.

Features

• Real-time Linux® operating system for Intel® and AMD based systems

• Field-proven Value-add Performance
  - Guaranteed event response times
  - Advanced shielding features
      - Processor, interrupt and local timer
      - Easy-to-use shielding API and GUI
  - NUMA performance optimization
  - User-level I/O
  - Frequency-based scheduling
  - Lockless kernel trace
  - Optimized graphics I/O
  - Cluster management
  - Preemptive, multithreaded, reentrant kernel
  - Priority inheritance
  - User-level preemption control
  - Post/Wait services
  - Minimal dispatch latencies
  - Dynamic and static load balancing

• Industry Standards
  - Linux Standard Base (LSB)
  - POSIX 1003.13 Profile 54
  - POSIX 1003.1 real-time and threads
  - Semaphores
  - Signals
  - Shared memory
  - Message queues
  - Memory locking
  - Asynchronous I/O
  - Synchronous I/O
  - Execution scheduling
  - High-resolution clocks and timers

• Single-vendor Support for All Linux Needs
  - Software maintenance services
  - Custom I/O drivers
  - Application rehosting
  - Consulting services

Benefits

Complete Development Environment

RedHawk Linux offers a full set of tools for efficient development of time-critical applications. Concurrent’s powerful NightStar application development tool set provides a robust graphic interface for nonintrusive control, monitoring, analysis and debugging of multi-threaded and multi-core applications. NightStar offers advanced debugging features such as lockless kernel trace. In addition to the GNU C, C++, and Fortran compilers, Concurrent’s MAXAda 95 language environment is optionally available. RedHawk also supports the popular Intel C/C++ and Fortran compilers.

Scalable SMP and Processor Shielding

In tightly-coupled symmetric multiprocessing systems, RedHawk Linux allows individual CPUs and cores to be shielded from local timers, interrupts, daemons, bottom halves and other Linux tasks. RedHawk’s comprehensive processor shielding features provide a highly deterministic execution environment where interrupt response is guaranteed. Unlike other distributions, RedHawk offers a fieldproven, easy-to-use shielding API with both command-line and graphical tool user interfaces.

Multithreading and Preemption

RedHawk Linux allows multiple processes to execute in the kernel simultaneously. The kernel protects key data structures and critical sections of code with semaphores and spinlocks to preserve system integrity.

Processes executing in the RedHawk kernel can be preempted, i.e. forced to relinquish a CPU involuntarily. The RedHawk kernel can transfer control from a lower-priority process to a higher-priority process except when the lower priority process is executing in a critical kernel section. To provide deterministic response, many critical sections of the kernel have been tuned and optimized to dramatically shorten non-preemptable conditions. These changes are key to allowing a high-priority process to respond immediately to an external event, even when the CPU is currently in use.

Semaphores internal to RedHawk Linux also support priority inheritance to prevent priority inversion when multiple threads of an application are competing for operating system resources.

Single Kernel Environment

RedHawk is a complete Linux distribution designed to fully support time-critical applications. RedHawk provides a true single-kernel programming environment that directly controls all system operation. Complex time-critical applications often require that high-speed file I/O, networking and graphics be performed deterministically together with real-time task scheduling. Only RedHawk’s single-kernel design ensures determinism and high-speed performance of all these features.

Frequency-Based Scheduler

RedHawk’s Frequency-Based Scheduler (FBS) is a high-resolution task scheduler that enables the user to run processes in cyclical execution patterns. FBS controls the periodic execution of multiple, coordinated processes utilizing major and minor cycles with overrun detection. A performance monitor is also provided to view CPU utilization during each scheduled execution frame.

RCIM Support

On Concurrent iHawk real-time multiprocessors, RedHawk supports the Real-Time Clock & Interrupt Module (RCIM), a multifunction card designed for time-critical applications that require rapid response to external events. Eight programmable timers and twelve input and output external interrupt lines are available. Any interrupt source can be distributed to other iHawks for synchronizing multi-system applications. The RCIM includes a high-resolution synchronized clock to provide a common time base across multiple systems. On-thewire time stamps allow RedHawk to provide for high-resolution NTP synchronization. RCIM options include a GPS module for synchronizing with GPS standard time and high-stability crystal oscillators to provide for accurate time keeping without an external time source.

I/O Enhancements

RedHawk supports Linux user-level (UIO) device drivers. RedHawk’s UIO facility provides a kernel driver stub that can be used with user code to develop a user-space driver for almost any type of hardware. RedHawk also includes the latest available NVIDIA graphics drivers specially optimized for realtime performance by Concurrent. The enhanced graphics driver allows applications to achieve maximum determinism during image rendering.

Non-Uniform Memory Access (NUMA) Optimization

The standard Linux NUMA implementation does not offer a mechanism to ensure that all pages of a real-time process are local to a given NUMA node and ensure that no other process’ pages are using that same node. RedHawk’s NUMA optimization features dramatically improve the determinism of real-time process memory access on NUMA architectures. RedHawk can automatically duplicate libraries and other modules as needed and hold them simultaneously in multiple nodes to maximize performance.

Red Hawk Cluster Management Software

RedHawk’s cluster manager software allows users to install and configure systems as highly-integrated, highperformance computing clusters. Cluster manager includes a mechanism for network booting multiple nodes with the same version of RedHawk. Cluster management software products also include Global File System, High-Availability NFS and OpenFabrics Enterprise Distribution packages.

NightStar Application Debelopment Tools

Concurrent’s NightStar is a powerful, integrated tool set for developing time-critical Linux applications. NightStar tools run with minimal intrusion, thus preserving application execution behavior and determinism. Users can quickly and easily debug, monitor, schedule, analyze and tune applications in real-time.