IRQ latency and context switching on mvme5500 (was Re: RTEMS mvme5500 bsp)

[Karel Gardas]

Kate,

your experiments looks nice and in favour of RTEMS, but do you have any 
numbers comparing latencies between receiving ethernet packet and reading 
data from the socket in an application? Or perhaps simple latency 
meassurements between two RTEMS and two vxWorks BSPs connected by ethernet 
with as simple as possible echo service should be fine too and giving 
clear picture.

Thanks,
Karel

On Wed, 27 Jul 2005, Kate Feng wrote:

>
>>  Interested, yes, but I really have no time right now
>> to have a closer look at it -- can you summarize the results?
>
> Based on the test  result, it shows that  RTEMS-mvme5500 is
> more deterministic  and  steadier than vxWorks-mvme5500
> for the highest priority task.  For  both  the idle  and loaded system,
> RTEMS-mvme5500 "GUARANTEED"  twice or three times
> faster response time in a steadier state.     The "worst case" is a
> critical factor  in consideration of the real-time  system.
>
>> MVME5500    Interrupt   Latency    |   Context Switching
>> _________________________________________________________
>>                            max      (average)   |     max    (average)
>>
>> _________________________________________________________
>> Idle System:                                      |
>>
>> RTEMS          5.04       (3.45)           |    6.80     (0.96)
>>
>> vxWorks       12.13       (1.58)          |   18.68     (0.91)
>>
>> _________________________________________________________
>> Loaded System:
>>
>> RTEMS          8.17       (3.74)          |   24.88     (1.69)
>>
>> vxWorks       22.49       (2.04)         |   40.76     (4.1)
>> _________________________________________________________
>>
>> ** All units are in usec.
>
>

--
Karel Gardas                  kgardas at objectsecurity.com
ObjectSecurity Ltd.           http://www.objectsecurity.com