forked from Imagelibrary/rtems
f39f667a69
The function to change a thread priority was too complex. Simplify it with a new scheduler operation. This increases the average case performance due to the simplified logic. The interrupt disabled critical section is a bit prolonged since now the extract, update and enqueue steps are executed atomically. This should however not impact the worst-case interrupt latency since at least for the Deterministic Priority Scheduler this sequence can be carried out with a wee bit of instructions and no loops. Add _Scheduler_Change_priority() to replace the sequence of - _Thread_Set_transient(), - _Scheduler_Extract(), - _Scheduler_Enqueue(), and - _Scheduler_Enqueue_first(). Delete STATES_TRANSIENT, _States_Is_transient() and _Thread_Set_transient() since this state is now superfluous. With this change it is possible to get rid of the SCHEDULER_SMP_NODE_IN_THE_AIR state. This considerably simplifies the implementation of the new SMP locking protocols.
monitor task
The monitor task is an optional task that knows about RTEMS
data structures and can print out information about them.
It is a work-in-progress and needs many more commands, but
is useful now.
The monitor works best when it is the highest priority task,
so all your other tasks should ideally be at some priority
greater than 1.
To use the monitor:
-------------------
#include <rtems/monitor.h>
...
rtems_monitor_init(0);
The parameter to rtems_monitor_init() tells the monitor whether
to suspend itself on startup. A value of 0 causes the monitor
to immediately enter command mode; a non-zero value causes the
monitor to suspend itself after creation and wait for explicit
wakeup.
rtems_monitor_wakeup();
wakes up a suspended monitor and causes it to reenter command mode.
Monitor commands
----------------
The monitor prompt is 'rtems> '.
Can abbreviate commands to "uniquity"
There is a 'help' command. Here is the output from various
help commands:
Commands (may be abbreviated)
help -- get this message or command specific help
task -- show task information
queue -- show message queue information
symbol -- show entries from symbol table
pause -- pause monitor for a specified number of ticks
fatal -- invoke a fatal RTEMS error
task [id [id ...] ]
display information about the specified tasks.
Default is to display information about all tasks on this node
queue [id [id ... ] ]
display information about the specified message queues
Default is to display information about all queues on this node
symbol [ symbolname [symbolname ... ] ]
display value associated with specified symbol.
Defaults to displaying all known symbols.
pause [ticks]
monitor goes to "sleep" for specified ticks (default is 1)
monitor will resume at end of period or if explicitly awakened
fatal [status]
Invoke 'rtems_fatal_error_occurred' with 'status'
(default is RTEMS_INTERNAL_ERROR)
continue
put the monitor to sleep waiting for an explicit wakeup from the
program running.
Sample output from 'task' command
---------------------------------
rtems> task
ID NAME PRIO STAT MODES EVENTS WAITID WAITARG NOTES
------------------------------------------------------------------------
00010001 UI1 2 READY P:T:nA NONE15: 0x40606348
00010002 RMON 1 READY nP NONE15: 0x40604110
'RMON' is the monitor itself, so we have 1 "user" task.
Its modes are P:T:nA which translate to:
preemptable
timesliced
no ASRS
It has no events.
It has a notepad value for notepad 15 which is 0x40606348
(this is the libc thread state)