Optimization

AN3423

10/13

Doc ID 018987 Rev 2

The code that adjusts the interrupt levels in GetResource and ReleaseResource is omitted.

●

OS_EXCLUDE_SHUTDOWNHOOK

The code that calls the ShutdownHook is omitted.

●

OS_EXCLUDE_STACKCHECK

All software stack checking is omitted.

●

OS_EXCLUDE_STARTUPHOOK

The code that calls the StartupHook in StartOS is omitted.

●

OS_EXCLUDE_SWCOUNTER

All code related to Software Counters (including the IncrementCounter API) is omitted.

●

OS_EXCLUDE_TIMINGPROTECTION

All the code that implements execution-time protection (execution budget, resource and

interrupt lock timing) is omitted.

●

OS_EXCLUDE_USERTASKRETURN

The code that handles a return from a task's main function is omitted. If a task fails to call

TerminateTask and simply returns from its main function, the result is undefined but most

likely result in the task entering an endless loop, which lock out equal and lower priority

tasks.

●

OS_EXCLUDE_AGGREGATELIMIT

No longer used. The aggregate execution-time limit was removed in AUTOSAR 3.0.

2.7

Disadvantages

The main disadvantage of using the custom kernel is the build time. Building a kernel library

under Windows with EB's customer “make” environment can take a good few minutes -

although building on Linux with a simplified make environment can be achieved in under 10

seconds. If compile time is a problem, it is better to use a standard library in the early stages

of a project, when the configuration is undergoing change. If optimization is used extensively

while the configuration is changing, the AUTOSAR OS' library directory fills up with the

different library versions and the corresponding object files, but these can be deleted if disk

space becomes a problem.