The Cobalt core is a co-kernel which supplements the Linux kernel for delivering real-time services with very low latency. More...
Collaboration diagram for Cobalt kernel:
|
Modules | |
| Asynchronous Procedure Calls | |
| Services for scheduling function calls in the Linux domain. | |
| In-kernel arithmetics | |
| A collection of helpers performing arithmetics not implicitly available from kernel context via GCC helpers. | |
| Buffer descriptor | |
| Abstraction for copying data to/from different address spaces. | |
| Clock services | |
| Debugging services | |
| Dynamic memory allocation services | |
| The implementation of the memory allocator follows the algorithm described in a USENIX 1988 paper called "Design of a General
Purpose Memory Allocator for the 4.3BSD Unix Kernel" by Marshall K. | |
| Interrupt management | |
| Locking services | |
| The Xenomai core deals with concurrent activities from two distinct kernels running side-by-side. | |
| Lightweight key-to-object mapping service | |
| A map is a simple indexing structure which associates unique integer keys with pointers to objects. | |
| Registry services | |
| The registry provides a mean to index object descriptors on unique alphanumeric keys. | |
| Thread scheduling control | |
| Synchronous I/O multiplexing | |
| This module implements the services needed for implementing the POSIX select() service, or any other event multiplexing services. | |
| Thread synchronization services | |
| Thread services | |
| Timer services | |
| The Xenomai timer facility depends on a clock source (xnclock) for scheduling the next activation times. | |
| Virtual file services | |
| Virtual files provide a mean to export Xenomai object states to user-space, based on common kernel interfaces. | |
Detailed Description
The Cobalt core is a co-kernel which supplements the Linux kernel for delivering real-time services with very low latency.
It implements a set of generic RTOS building blocks, which the Cobalt/POSIX and Cobalt/RTDM APIs are based on. Cobalt has higher priority over the Linux kernel activities.
Dual kernel service tags
The Cobalt kernel services may be restricted to particular calling contexts, or entail specific side-effects.To describe this information, each service documented by this section bears a set of tags when applicable.The table below matches the tags used throughout the documentation with the description of their meaning for the caller.
- Context tags
Tag Context on entry primary-only Must be called from a Cobalt task in primary mode primary-timed Requires a Cobalt task in primary mode if timed coreirq-only Must be called from a Cobalt IRQ handler secondary-only Must be called from a Cobalt task in secondary mode or regular Linux task rtdm-task Must be called from a RTDM driver task mode-unrestricted May be called from a Cobalt task in either primary or secondary mode task-unrestricted May be called from a Cobalt or regular Linux task indifferently unrestricted May be called from any context previously described atomic-entry Caller must currently hold the big Cobalt kernel lock (nklock)
- Possible side-effects
Tag Description might-switch The Cobalt kernel may switch context
