Re: [ECOS] High priority thread versus network

[Wayne Visser <wvisser@lszpaper.com>]

Thanks for the tips, Robin.  You may be shooting in the dark, but I *am* 
in the dark! ;-)

You're right, it does look like a stack overflow, but I have assertions 
enabled (CYGDBG_USE_ASSERTS) and CYGFUN_KERNEL_THREADS_STACK_CHECKING is 
also enabled.  I've seen no asserts or panics being raised to date.  Are 
there other assertions I've missed?

I'm using a separate interrupt stack (size = 4096).

I've gone ahead and increased the size of the NET_THREAD and 
NET_FAST_THREAD and am currently re-running the tests.

   -- Wayne

Robin Randhawa wrote:
> 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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