The current implementation of task migration in RTEMS has some
implications with respect to the interrupt latency. It is crucial to
preserve the system invariant that a task can execute on at most one
processor in the system at a time. This is accomplished with a boolean
indicator in the task context. The processor architecture specific
low-level task context switch code will mark that a task context is no
longer executing and waits that the heir context stopped execution
before it restores the heir context and resumes execution of the heir
task. So there is one point in time in which a processor is without a
task. This is essential to avoid cyclic dependencies in case multiple
tasks migrate at once. Otherwise some supervising entity is necessary to
prevent life-locks. Such a global supervisor would lead to scalability
problems so this approach is not used. Currently the thread dispatch is
performed with interrupts disabled. So in case the heir task is
currently executing on another processor then this prolongs the time of
disabled interrupts since one processor has to wait for another
processor to make progress.
It is difficult to avoid this issue with the interrupt latency since
interrupts normally store the context of the interrupted task on its
stack. In case a task is marked as not executing we must not use its
task stack to store such an interrupt context. We cannot use the heir
stack before it stopped execution on another processor. So if we enable
interrupts during this transition we have to provide an alternative task
independent stack for this time frame. This issue needs further
investigation.
Use "cpu" for an arbitrary Per_CPU_Control variable.
Use "cpu_self" for the Per_CPU_Control of the current processor.
Use "cpu_index" for an arbitrary processor index.
Use "cpu_index_self" for the processor index of the current processor.
Use "cpu_count" for the processor count obtained via
_SMP_Get_processor_count().
Use "cpu_max" for the processor maximum obtained by
rtems_configuration_get_maximum_processors().
Rename rtems_smp_get_processor_count() in rtems_get_processor_count().
Make rtems_get_processor_count() a function in uni-processor
configurations to enable ABI compatibility with SMP configurations.
Move implementation specific parts of object.h and object.inl into new
header file objectimpl.h. The object.h contains now only the
application visible API.
Move implementation specific parts of watchdog.h and watchdog.inl into
new header file watchdogimpl.h. The watchdog.h contains now only the
application visible API.
Rename in rtems_smp_get_processor_count(). Always provide
<rtems/score/smp.h> and <rtems/rtems/smp.h>. Add
_SMP_Get_processor_count(). This function will be a compile time
constant defined to be one on uni-processor configurations. This allows
iterations over all processors without overhead on uni-processor
configurations.
Script does what is expected and tries to do it as
smartly as possible.
+ remove occurrences of two blank comment lines
next to each other after Id string line removed.
+ remove entire comment blocks which only exited to
contain CVS Ids
+ If the processing left a blank line at the top of
a file, it was removed.
* libmisc/cpuuse/cpuusagereport.c: Fix calculation in case a thread
dispatch happends in the meantime. The percent values will not sum up
to one hundred percent.
* libcsupport/src/privateenv.c, libmisc/cpuuse/cpuusagereport.c,
posix/Makefile.am, posix/include/rtems/posix/key.h,
posix/src/keycreate.c, posix/src/keydelete.c,
score/src/iterateoverthreads.c: Since removing ITRON, the loop over
all APIs for tasks has a path that cannot be reached. Either modify
the code or mark tests for NULL as RTEMS_DEBUG.
* posix/src/keyfreememory.c: New file.
* configure.ac, libcsupport/src/__times.c,
libmisc/cpuuse/cpuusagedata.c, libmisc/cpuuse/cpuusagereport.c,
libmisc/cpuuse/cpuusagereset.c, rtems/include/rtems/rtems/ratemon.h,
rtems/include/rtems/rtems/types.h, rtems/src/ratemongetstatistics.c,
rtems/src/ratemongetstatus.c, rtems/src/ratemonperiod.c,
rtems/src/ratemonreportstatistics.c,
score/include/rtems/score/thread.h, score/src/threaddispatch.c,
score/src/threadinitialize.c, score/src/threadtickletimeslice.c:
Changed the configuration of statistics granularity to use just one
define.
* libmisc/serdbg/termios_printk.c, libmisc/serdbg/termios_printk.h:
Fixed incompatible return value.
* libmisc/cpuuse/cpuusagereport.c: Changed output format.
* libmisc/Makefile.am, libmisc/monitor/mon-editor.c: New file.
* libmisc/capture/capture-cli.c, libmisc/monitor/mon-command.c,
libmisc/monitor/mon-monitor.c, libmisc/monitor/mon-object.c,
libmisc/monitor/mon-prmisc.c, libmisc/monitor/mon-symbols.c,
libmisc/monitor/monitor.h, libmisc/shell/cat_file.c,
libmisc/shell/cmds.c, libmisc/shell/internal.h,
libmisc/shell/main_help.c, libmisc/shell/shell.c,
libmisc/shell/shell.h, libmisc/shell/shell_cmdset.c,
libmisc/shell/shell_getchar.c, libmisc/shell/str2int.c: Various global
data is now read only. Added 'const' qualifier to many pointer
parameters. It is no longer possible to remove monitor commands.
Moved monitor line editor into a separate file to avoid unnecessary
dependencies.
* libcsupport/src/__times.c, libmisc/cpuuse/cpuusagereport.c,
libmisc/cpuuse/cpuusagereset.c, posix/src/clockgettime.c,
posix/src/pthread.c, posix/src/timersettime.c,
rtems/include/rtems/rtems/ratemon.h,
rtems/src/clockgetsecondssinceepoch.c, rtems/src/clockgetuptime.c,
rtems/src/ratemongetstatus.c, rtems/src/ratemonperiod.c,
rtems/src/ratemonreportstatistics.c, rtems/src/taskwakewhen.c,
rtems/src/timerfirewhen.c, rtems/src/timerserver.c,
rtems/src/timerserverfirewhen.c, score/Makefile.am,
score/preinstall.am, score/include/rtems/score/thread.h,
score/include/rtems/score/tod.h, score/src/coretod.c,
score/src/coretodget.c, score/src/coretodgetuptime.c,
score/src/coretodset.c, score/src/coretodtickle.c,
score/src/threaddispatch.c, score/src/threadinitialize.c: Add
SuperCore handler Timestamp to provide an opaque class for the
representation and manipulation of uptime, time of day, and the
difference between two timestamps. By using SuperCore Timestamp, it
is clear which methods and APIs really have to be struct timespec and
which can be in an optimized native format.
* score/include/rtems/score/timestamp.h,
score/src/coretodgetuptimetimespec.c: New files.
* libcsupport/src/__times.c, libmisc/cpuuse/cpuusagereport.c,
libmisc/cpuuse/cpuusagereset.c, libmisc/monitor/mon-task.c,
rtems/include/rtems/rtems/ratemon.h, rtems/src/ratemongetstatus.c,
rtems/src/ratemonperiod.c, score/include/rtems/score/thread.h,
score/src/threaddispatch.c, score/src/threadinitialize.c,
score/src/threadtickletimeslice.c: Add typedefs for cpu usage and
period timing statistics. Also renamed related variables and
structure members so they are the same whether you are using
nanosecond (e.g. struct timespec) or ticks (e.g. uint32_t)
granularity. This lays the groundwork for future cleanup.
* libcsupport/src/printk.c: Added width and padding for %s.
* libmisc/cpuuse/cpuusagereport.c: Support object names that are
strings longer than 4 chanracters.
* libmisc/cpuuse/cpuusagereport.c, rtems/src/ratemonreportstatistics.c:
Cleaned up reports and fixed a bug related the printf format which
resulted in lack of leading zeroes and misleading magnitude.
* score/src/timespecdivide.c: Fixed bugs related to zero divide case.
* libcsupport/Makefile.am, libcsupport/src/printk.c:
* libcsupport/src/printk_plugin.c: New file.
include/rtems/bspIo.h, libmisc/cpuuse/cpuusagereport.c,
libmisc/cpuuse/cpuuse.h, libmisc/stackchk/check.c,
libmisc/stackchk/stackchk.h: rtems/include/rtems/rtems/ratemon.h,
rtems/src/ratemonreportstatistics.c: Added capability to specify
your own "printf" routine to various reporting functions. This
added an XXX_with_plugin as the underlying implementation for
+ rtems_rate_monotonic_report_statistics
+ rtems_stack_checker_report_usage
+ rtems_cpu_usage_report
As demonstration, the http netdemo can now print out stack
and cpu usage reports.
* libmisc/cpuuse/cpuusagereport.c, libmisc/cpuuse/cpuusagereset.c,
score/src/timespecdivide.c: Fix various math and reporting bugs. Now
the time appears to be reported correctly and add up to what is
expected.
* libmisc/Makefile.am, libmisc/cpuuse/cpuusagereport.c,
libmisc/cpuuse/cpuusagereset.c: Fix bug where cpu usage calculation
was always using uptime not time since last cpu usage reset when
using nanoseconds granularity.
* libmisc/cpuuse/cpuusagedata.c: New file.
* ChangeLog, configure.ac, libcsupport/src/__times.c,
libmisc/cpuuse/cpuuse.c, libmisc/stackchk/check.c,
rtems/include/rtems/rtems/ratemon.h, rtems/src/ratemongetstatus.c,
rtems/src/ratemonperiod.c, rtems/src/ratemonreportstatistics.c,
rtems/src/ratemonresetall.c, rtems/src/ratemontimeout.c,
score/Makefile.am, score/include/rtems/score/thread.h,
score/include/rtems/score/timespec.h, score/src/threaddispatch.c,
score/src/threadinitialize.c, score/src/threadtickletimeslice.c,
score/src/timespecdivide.c: Add nanoseconds granularity to the rate
monotonic period statistics and CPU usage statistics. This capability
is enabled by default although may be conditionally disabled by the
user. It could be too much overhead on small targets but it does not
appear to be bad in early testing. Its impact on code size has not
been evaluated either. It is possible that both forms of statistics
gathering could be disabled with further tweaking of the conditional
compilation.
* score/src/timespecdividebyinteger.c: New file.
* libmisc/cpuuse/cpuuse.c, libmisc/stackchk/check.c,
libmisc/stackchk/stackchk.h: Clean up as side-effect of making them
suitable for inclusion in the Users Guide.
* libmisc/cpuuse/cpuuse.c, libmisc/cpuuse/cpuuse.h: Promote CPU Usage
to first class citizen. Rename to start with rtems_ and include
documentation in user guide.
