Again, thanks to those who sent corrections/suggestions.
The table and API-differences below are getting smoother.
I hope it has converged to something useful to other people
in this list.
As we all (probably) expected, the differences between RTL
and RTAI are NOT that many (refer to RTLv2 and RTAIv6). As
a matter of fact, in my opinion the "only" discussion in this
list should be around POSIX compliance, once that this should
be the common denominator and, at the same time, the unifier
between both implementations. Other than that there are some
"unimportant" details such as unified header files, similar
installations, etc. But yet, that should come naturally after.
Guilherme
----------------------------------------------------------------------------------
| | I | S | Sched. | S |Po- |pthre|F | Shr| FP | GPL | Ker- | 486 | PPC |
| | P | e | | | M | six | -| I | Mem| | | nel | | |
| | C | m |Per.| OS | P | |ads | FO| | | | | | |
-------------------|--------------------------------------------------------------
| | | | | | | | | | | | | | | |
| RTL | o | o | w/ | w/ | n | * | n | y | o | y | y | 2.0.x | y | n |
| v1 | | |8254|8254| | | | | | | | | | |
| | | | | | | | | | | | | | | |
----------------------------------------------------------------------------------
| | | | | w/ | | | | | | | | | | |
| | | | |8254| | | | | | | | | | |
| | | | | + | | | | | | | | | | in |
| | | | w/ |TSC | | | | | | | | | | |
| RTL | o | o | | | y | * | ** | y | o | y | y | 2.2.x | n |deve-|
| v2 | | |8254|APIC| | | | | | | | | | |
| | | | | in | | | | | | | | | |lopm.|
| | | | |SMP | | | | | | | | | | |
| | | | | | | | | | | | | | | |
----------------------------------------------------------------------------------
| | | | |8254| | | | | | | | | | |
| | | | | in | | | | | | | | | | |
| | | | |UP -| | | | | | | | | | |
| | | | |SMP | | | | | | | | | | |
| | | | w/ | & | | | | | | | | | y | |
| RTAI| y | y | |MUP | y | * | ** | y | o | y | y | 2.2.x | | n |
| v.6 | | |8254| | | | | | | | | |(for | |
| | | | |APIC| | | | | | | | |1 CPU| |
| | | | | in | | | | | | | | |only)| |
| | | | |SMP | | | | | | | | | | |
| | | | | & | | | | | | | | | | |
| | | | |MUP | | | | | | | | | | |
----------------------------------------------------------------------------------
y - embeded in the RT modules
n - not implemented
o - optional (it can be "insmod'ed" separately)
* - in RTAI, a POSIX lite API is implemented on top of the original API
in RTL, the original API is implemented on top of a POSIX lite API.
** - RTAI - dynamic thread creation, conditional variables and priority
inheritance mutex,
RTL - static thread creation.
Original API comparison
=======================
What follows is a comparison btw the two original APIs (RTAI
and RTLv1). We are not listing the POSIX (lite) API present in
both recent releases of RTAI and RTL.
set up peridic mode
------------------
RTL:
RTIME task_ticks;
task_ticks = (RT_TICKS_PER_SEC/FREQ);
rtl_set_periodic_mode(task_ticks);
RTAI:
RTIME task_ticks;
rt_set_periodic_mode(void);
task_ticks = nano2count(1000000000/FREQ)
start_rt_timer(task_ticks)
Tell Linux you will be using the FPU
--------------------------------------
RTL:
??
RTAI:
rt_linux_use_fp(1)
initialise a task
-----------------
RTL:
rt_task_init( RT_TASK *task,
void (*fn)(int),
int data,
int stack_size,
int priority )
If it uses the FPU, add:
rt_task_use_fp( RT_TASK *task, 1 )
RTAI:
rt_task_init( RT_TASK *task,
void (*fn)(int),
int data,
int stack_size,
int priority,
int uses_fpu,
void (*signal)(void) )
set a (periodic) task running
-----------------------------
RTL/RTAI:
rt_task_make_periodic( RT_TASK *task,
RTIME start_time_ticks,
RTIME period_ticks)
suspend a running task until the next tick
-------------------------------------------
RTL:
rt_task_wait(void)
RTAI:
rt_task_wait_period(void)
cleanup/stop a task
--------------------
RTAI: stop_rt_timer(void)
RTL/RTAI: rt_task_suspend(RT_TASK *task)
rt_task_delete( RT_TASK *task)
create a fifo
--------------
RTL:
rtf_create(unsigned int fifo, int fifo_size)
RTAI:
rtf_create_using_bh(unsigned int, int size, 0)
NOTE: both can be used with the simple rtf_create, but the behaviour is
different. Under RTAI, a user task will only be woken up at the next
run of schedule (this is an intended feature). To get the same effect
of waking up as soon as possible, use the above code.
put data to a fifo
-------------------
RTL/RTAI:
rtf_put(unsigned int fifo, void *buf, int count)
get data from a fifo
----------------------
RTL/RTAI:
rtf_get(usigned int fifo, void *buf, int count)
destroy a fifo
---------------
RTL/RTAI:
rtf_destroy(usigned int fifo)
Filename comparison
===================
Another problem is the name and location of files. This means that
Makefiles and code has to be changed to locate the different include
files.
Header names
-----------
RTL:
rtl_fifo.h, rtl_sched.h
RTAI:
rtai_fifos.h, rtai_sched.h
Note: in addition you must also include rtai.h first for RTAI.
-------------< G. N. DeSouza >-------------
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-------------< G. N. DeSouza >-------------
---------< [EMAIL PROTECTED]>---------
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