[ECOS] High priority thread versus network

[Wayne Visser <wvisser@lszpaper.com>]

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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