RES: Different tick interval with the same application between RTEMS 4.10.0 and 4.10.2?

Joel Sherrill joel.sherrill at OARcorp.com
Mon May 21 13:13:53 CDT 2012


On 05/21/2012 12:55 PM, Fabrício de Novaes Kucinskis wrote:
>
> Hi Joel, and thanks for your answer,
>
> The “one second” reference I used is real time (ERC32 BSP). When 
> simulating (SIS BSP), things run a little faster. But not as fast as 
> what we are seeing now.
>
> We checked (both a dump of the .exe and with a breakpoint at 
> Clock_isr), and the fast idle mode is not #included in the application 
> compiled for SIS.
>
> Could this be a side-effect of the nanoseconds change? I don’t think 
> so, as we’re not enabling the extension. But don’t know where else to 
> look for.
>
I don't think so either. The timer should be programmed with the same value
on both sis and real hardware.

That's the only thing to check.

By any chance did the version of gdb change? Or did the binary change?
I am thinking that an sis with 64-bit internal cycle counter might be faster
than the version with 32-bit internal cycle counter.
>
> We also compiled the same application with both versions of RTEMS and 
> run in an ERC32 board. Both run at the same 1-second interval. As this 
> is our main target, the issue with the simulator shouldn’t bother us 
> too much. But I think it’s always important to report to the list when 
> something doesn’t work as expected – maybe the observed behavior point 
> to something to be improved or fixed.
>
> Thanks again,
>
> Fabrício.
>
> *De:*Joel Sherrill [mailto:joel.sherrill at oarcorp.com]
> *Enviada em:* segunda-feira, 21 de maio de 2012 11:26
> *Para:* Fabrício de Novaes Kucinskis
> *Cc:* 'RTEMS Users'
> *Assunto:* Re: Different tick interval with the same application 
> between RTEMS 4.10.0 and 4.10.2?
>
> On 05/21/2012 08:49 AM, Fabrício de Novaes Kucinskis wrote:
>
> Hi all,
>
> We've just upgraded our development environment from RTEMS 4.10.0 to 
> RTEMS 4.10.2. As always, an interesting issue has raised! ;-)
>
> We use the ERC32 and SIS BSPs. After the upgrade, a simple test 
> application that prints a clock once per second started to print the 
> clock values almost two times faster on SIS. The application gets the 
> number of ticks per second and uses it in the rtems_task_wake_after 
> directive.
>
> When on any simulator, there is always the possibility that somehow 
> the fast idle mode
> in the clock driver got turned on.
>
> To determine if the issue was on SIS or RTEMS, we run in the 4.10.2 
> environment the previous version of the test, compiled with RTEMS 
> 4.10.0, and the task runs once per second. Also, the number of ticks 
> per second reported in both versions is the same.
>
>
> Is this once per second in simulated or real time?
>
> Set a break point at Clock_isr and see if it is doing the fast idle mode.
>
>
>
> Looking at the release notes, we've found a number of changes/fixes 
> related with ticks and time since 4.10.0. But it seems that none of 
> them is related to what I report here.
>
> I looked at the diff files and the only changes are fixing bugs
> related to nanoseconds since last tick when you ask on the
> edge of a tick interrupt occurring.
>
> Is this something to be expected when upgrading? Am I missing some 
> change in the configuration?
>
> Thanks in advance and best regards,
>
> Fabrício de Novaes Kucinskis.
>
>
>
>
> -- 
> Joel Sherrill, Ph.D.             Director of Research&   Development
> joel.sherrill at OARcorp.com  <mailto:joel.sherrill at OARcorp.com>         On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>      Support Available             (256) 722-9985
>   


-- 
Joel Sherrill, Ph.D.             Director of Research&   Development
joel.sherrill at OARcorp.com        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
     Support Available             (256) 722-9985


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