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 FMLP
	bool "FMLP support"
	depends on NP_SECTION
	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_TASK_TRACE_SHIFT
       int "Buffer size for sched_trace_xxx() events"
       depends on SCHED_TASK_TRACE
       range 8 13
       default 9
       help

         Select the buffer size of sched_trace_xxx() events as a power of two.
	 These buffers are statically allocated as per-CPU data. Each event
	 requires 24 bytes storage plus one additional flag byte. Too large
	 buffers can cause issues with the per-cpu allocator (and waste
	 memory). Too small buffers can cause scheduling events to be lost. The
	 "right" size is workload dependent and depends on the number of tasks,
	 each task's period, each task's number of suspensions, and how often
	 the buffer is flushed.

	 Examples: 12 =>   4k events
		   10 =>   1k events
		    8 =>  512 events

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.

config SCHED_DEBUG_TRACE_SHIFT
       int "Buffer size for TRACE() buffer"
       depends on SCHED_DEBUG_TRACE
       range 14 22
       default 18
       help

	Select the amount of memory needed per for the TRACE() buffer, as a
	power of two. The TRACE() buffer is global and statically allocated. If
	the buffer is too small, there will be holes in the TRACE() log if the
	buffer-flushing task is starved.

	The default should be sufficient for most systems. Increase the buffer
	size if the log contains holes. Reduce the buffer size when running on
	a memory-constrained system.

	Examples: 14 =>  16KB
		  18 => 256KB
		  20 =>   1MB

        This buffer is exported to usespace using a misc device as
        'litmus/log'. On a system with default udev rules, a corresponding
        character device node should be created at /dev/litmus/log. The buffer
        can be flushed using cat, e.g., 'cat /dev/litmus/log > my_log_file.txt'.

endmenu

endmenu