Experimental Physics and
Industrial Control System

Hi Andrew,
hi Eric,

thank you for your reply.

Adding operating system dependent code to my application to set the
priority would be a solution of course.

However, the intention of EPICS OSI is that I don't have to do that. If
there was a possibility to
specify the thread priority directly, I wouldn't have to include system
headers or call system functions
directly. If EPICS OSI was changed or extended, my code would look like
this:

#if defined(vxWorks)
  #define GPS_WRITER_PRIO 67
#elif defined(RTEMS)
  #define GPS_WRITER_PRIO 123
#endif

epicsThreadCreate("mC Writer", GPS_WRITER_PRIO,
                  epicsThreadGetStackSize(epicsThreadStackSmall),
                  (EPICSTHREADFUNC) gps_writer, NULL))

Isn't this nicer than having to call taskPrioritySet or
rtems_task_set_priority directly as
in your quoted mail below ?

The way epicsThreadCreate in EPICS OSI handles priorities at least in
the vxWorks and RTEMS
implementation seems to be a design flaw for me. Why not fix it ?

Greetings,

  Goetz

On 02/20/2012 10:46 PM, Andrew Johnson wrote:

Hi Goetz,

On 2012-02-20 Eric Norum wrote:

How about calling the RTEMS rtems_task_set_priority routine from the
beginning of your new thread?

I think I prefer Eric's suggestion to adding anything to the epicsThread API.

For each particular OS you will already need an OS-specific numeric priority,
so you'll have to have OS-specific code in the source file anyway.  In that
case you can just call the OS-specific API to change the new thread's
priority.  For vxWorks and RTEMS that would mean adding something like this:

#if defined(vxWorks)
     taskPrioritySet(0, 66);
#elif defined(RTEMS)
     {
         rtems_task_priority old;
         rtems_task_set_priority(RTEMS_SELF, 66,&old);
     }
#endif

Now it's obvious that the this is OS-specific code, and the thread priority
can be easily set to whatever is appropriate for the OS.

- Andrew

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Replies:

Best pratices for compiling dbd files for asyn base device support Abadie Lana

Re: Problems with priorities in epicsThreadCreate (part of the EPICS OSI software layer) Andrew Johnson

References:

Problems with priorities in epicsThreadCreate (part of the EPICS OSI software layer) Goetz Pfeiffer

Re: Problems with priorities in epicsThreadCreate (part of the EPICS OSI software layer) Eric Norum

Re: Problems with priorities in epicsThreadCreate (part of the EPICS OSI software layer) Andrew Johnson

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