menu "LITMUS^RT" menu "Scheduling" config PLUGIN_CEDF bool "Clustered-EDF" depends on X86 && SYSFS default y help Include the Clustered EDF (C-EDF) plugin in the kernel. This is appropriate for large platforms with shared caches. On smaller platforms (e.g., ARM PB11MPCore), using C-EDF makes little sense since there aren't any shared caches. config PLUGIN_PFAIR bool "PFAIR" depends on HIGH_RES_TIMERS && !NO_HZ default y help Include the PFAIR plugin (i.e., the PD^2 scheduler) in the kernel. The PFAIR plugin requires high resolution timers (for staggered quanta) and does not support NO_HZ (quanta could be missed when the system is idle). If unsure, say Yes. config RELEASE_MASTER bool "Release-master Support" depends on ARCH_HAS_SEND_PULL_TIMERS default n help Allow one processor to act as a dedicated interrupt processor that services all timer interrupts, but that does not schedule real-time tasks. See RTSS'09 paper for details (http://www.cs.unc.edu/~anderson/papers.html). Currently only supported by GSN-EDF. endmenu menu "Real-Time Synchronization" config NP_SECTION bool "Non-preemptive section support" default n help Allow tasks to become non-preemptable. Note that plugins still need to explicitly support non-preemptivity. Currently, only GSN-EDF and PSN-EDF have such support. This is required to support the FMLP. If disabled, all tasks will be considered preemptable at all times. config SRP bool "Stack Resource Policy (SRP)" default n help Include support for Baker's Stack Resource Policy. Say Yes if you want FMLP local long critical section synchronization support. config PI_SEMAPHORES bool "Semaphores with Priority Inheritance" default n help Generalized support for all Litmus priority inheriting semaphore protocols. config FMLP bool "FMLP support" depends on NP_SECTION depends on PI_SEMAPHORES default n help Include support for deterministic multiprocessor real-time synchronization support. Say Yes if you want FMLP long critical section synchronization support. endmenu menu "Tracing" config FEATHER_TRACE bool "Feather-Trace Infrastructure" default y help Feather-Trace basic tracing infrastructure. Includes device file driver and instrumentation point support. There are actually two implementations of Feather-Trace. 1) A slower, but portable, default implementation. 2) Architecture-specific implementations that rewrite kernel .text at runtime. If enabled, Feather-Trace will be based on 2) if available (currently only for x86). However, if DEBUG_RODATA=y, then Feather-Trace will choose option 1) in any case to avoid problems with write-protected .text pages. Bottom line: to avoid increased overheads, choose DEBUG_RODATA=n. Note that this option only enables the basic Feather-Trace infrastructure; you still need to enable SCHED_TASK_TRACE and/or SCHED_OVERHEAD_TRACE to actually enable any events. config SCHED_TASK_TRACE bool "Trace real-time tasks" depends on FEATHER_TRACE default y help Include support for the sched_trace_XXX() tracing functions. This allows the collection of real-time task events such as job completions, job releases, early completions, etc. This results in a small overhead in the scheduling code. Disable if the overhead is not acceptable (e.g., benchmarking). Say Yes for debugging. Say No for overhead tracing. config SCHED_OVERHEAD_TRACE bool "Record timestamps for overhead measurements" depends on FEATHER_TRACE default n help Export event stream for overhead tracing. Say Yes for overhead tracing. config SCHED_DEBUG_TRACE bool "TRACE() debugging" default y help Include support for sched_trace_log_messageg(), which is used to implement TRACE(). If disabled, no TRACE() messages will be included in the kernel, and no overheads due to debugging statements will be incurred by the scheduler. Disable if the overhead is not acceptable (e.g. benchmarking). Say Yes for debugging. Say No for overhead tracing. endmenu endmenu