Intel IXP400 Threading and Locking Policy, Polled and Interrupt Operation, Statistics and MIBs

Intel® IXP400 Software

Software Architecture Overview

2.7Threading and Locking Policy

The software release 2.0 access-layer does not implement processes or threads. The architecture assumes execution within a preemptive multi-tasking environment with the existence of multiple- client threads and uses common, real-time OS functions — such as semaphores, task locking, and interrupt control — to protect critical data and procedure sequencing. These functions are not provided directly by the OS, but by the OS abstraction components.

2.8Polled and Interrupt Operation

It is possible to use access-layer components by running the Queue Manager in a polled mode or in an interrupt driven mode of operation. A customers application code may be invoked by registering with the callback mechanisms provided in the access-layer components. Access-layer components do not autonomously bind themselves to interrupts but generally may be dispatched by an interrupt service routine that is bound to the Queue Manager interrupts. Or, a timer-based task may periodically check the queue manager status and dispatch the access-layer components that are registered to specific queues. Refer to Chapter 18 for additional information.

All data path interfaces are executable in the context of both IRQ and FIQ interrupts, though not all operating systems may take advantage of FIQ interrupts in their default configuration.

2.9Statistics and MIBs

The software release 2.0 access-layer components only maintain statistics that access-layer clients cannot collect of their own accord. The access-layer components do not provide management interfaces (MIBs). Access-layer clients can use the statistics provided to implement their own MIBs.

April 2005	IXP400 Software Version 2.0	Programmer’s Guide
32	Document Number: 252539, Revision: 007