Re: [ECOS] High priority thread versus network

[Robin Randhawa <robin.randhawa@gmail.com>]

Hi.

Just some shots in the dark :

1. Have you enabled all assertions ? Checks for stack manipulation ?

2. Are you using a separate interrupt stack ?

3. Does changing the default stack size of the Network Thread make a
difference in either the exhibited phenomena and/or the time before the
system hangs up ?

The problem you face seems to be a stack overflow but there really isn't
sufficient data to state that as a fact.

I would try the above just to reduce some of the possibilities.

Cheers,
Robin

On Mon, 2007-05-07 at 08:53 -0400, Wayne Visser wrote:
> Hello all,
> 
> We're having a problem with an eCos app that has a relatively 
> long-running, high priority thread (runs at priority 2 every 10 ms and 
> takes about 4ms to complete).  Under high network loads, the app will 
> crash with no asserts or panics.  If the high priority thread is 
> disabled, the app will run fine for days without problem under high net 
> loads.  Conversely, without any networking activity, the app runs fine 
> for days.
> 
> We've stripped this down to a simple test app with two parts (a) the 
> high priority thread basically does nothing but consume CPU time:
> 
> static void
> high_thread( cyg_addrword_t arg )
> {
>    int i, j;
>    cyg_uint16 buf[1024];
> 
>    while (1)
>    {
>      for ( j=0; j<90; ++j )
>      {
>        for ( i=0; i<1024; ++i)
>          buf[i] = rand();
>      }
> 
>      cyg_thread_delay(1);
>    }
> }
> 
> and (b) several identical networking threads that do nothing but accept 
> client connections and echo data sent to them.
> 
> If several clients connect to the eCos app, a crash will occur in as 
> little as a few minutes (but sometimes hours).
> 
> So my question is this: Are there any known issues in running a high 
> priority thread with a relatively long running time?  i.e. this thread 
> is effectively blocking the network threads from running for up to 4ms. 
>   Will that create any known problems?
> 
> Thanks for any feedback.
> 
>    -- Wayne
> 
> 
> ps: Out target is i386 and the problem is evident with both 8139 and 
> 82559 ethernet drivers.  Curiously, the problem does NOT appear with the 
> 83816 ethernet driver.
> 
> 


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