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Joel Sherrill
c3330a88ee
* 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.
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-- $Id$
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Overview of newlib support (newlib is from CYGNUS)
Each task can have its own libc state including:
open stdio files
strtok
multi precision arithmetic state
etc.
This is implemented by a reentrancy data structure for each task.
When a task is "started" (in RTEMS sense) the reentrancy structure
is allocated. Its address is stored in notepad[NOTEPAD_LAST].
When task is switched to, the value of global variable _impure_ptr
is changed to the value of the new tasks reentrancy structure.
When a task is deleted
atexit() processing (for that task) happens
task's stdio buffers are flushed
When exit(3) is called
calling task's atexit processing done
global libc state atexit processing done
(this will include any atexit routines installed by drivers)
executive is shutdown
causes a context switch back to bsp land
NOTE:
libc extension are installed by bsp_libc_init()
iff we are using clock interrupts.
This hack is necessary to allow the tmtests to avoid
timing the extensions.