forked from Imagelibrary/rtems
d19cce29dc
Use a per-CPU thread dispatch disable level. So instead of one global thread dispatch disable level we have now one instance per processor. This is a major performance improvement for SMP. On non-SMP configurations this may simplifiy the interrupt entry/exit code. The giant lock is still present, but it is now decoupled from the thread dispatching in _Thread_Dispatch(), _Thread_Handler(), _Thread_Restart_self() and the interrupt entry/exit. Access to the giant lock is now available via _Giant_Acquire() and _Giant_Release(). The giant lock is still implicitly acquired via _Thread_Dispatch_decrement_disable_level(). The giant lock is only acquired for high-level operations in interrupt handlers (e.g. release of a semaphore, sending of an event). As a side-effect this change fixes the lost thread dispatch necessary indication bug in _Thread_Dispatch(). A per-CPU thread dispatch disable level greatly simplifies the SMP support for the interrupt entry/exit code since no spin locks have to be acquired in this area. It is only necessary to get the current processor index and use this to calculate the address of the own per-CPU control. This reduces the interrupt latency considerably. All elements for the interrupt entry/exit code are now part of the Per_CPU_Control structure: thread dispatch disable level, ISR nest level and thread dispatch necessary. Nothing else is required (except CPU port specific stuff like on SPARC).
This is the Real-Time Executive for Multiprocessing Systems (RTEMS). The version number for this software is indicated in the VERSION file. See the documentation manuals in doc/ with daily builds available online at http://rtems.org/onlinedocs/doc-current/share/rtems/html/ and released builds at http://www.rtems.org/onlinedocs/releases/ for information on building, installing, and using RTEMS. The INSTALL file tells you to come back here. See the RTEMS Wiki at http://wiki.rtems.org/wiki/index.php/Main_Page for community knowledge and tutorials. RTEMS Doxygen available at http://www.rtems.org/onlinedocs/doxygen/cpukit/html Get help on the mailing lists: * For general-purpose questions related to using RTEMS, use the rtems-users ml: http://www.rtems.org/mailman/listinfo/rtems-users * For questions and discussion related to development of RTEMS, use the rtems-devel ml: http://www.rtems.org/mailman/listinfo/rtems-devel See http://www.rtems.org/bugzilla/ to report a bug.