Montavista's "Open Source Real-Time Linux Project" again

Paolo Mantegazza mantegazza at aero.polimi.it
Fri Oct 15 12:01:29 CEST 2004


Thomas Gleixner wrote:
> On Fri, 2004-10-15 at 02:18, Karim Yaghmour wrote:
> 
>>Thomas Gleixner wrote:
>>
>>>Yeah, I know. I doubt that. 
>>
>>You doubt which part of what I said?
> 
> 
> ".. want to go ahead and show that it is deterministic, they can."
> 
> Show ? With a scope ?
> 
> 
>>>Provide a static codepath analysis for all execution paths and I might
>>>buy your arguments.
>>
>>Right, and then you have the nerve to lecture me about self-adulation ...
>>
>>I don't have the time to do this myself, but I'd really love to plug a
>>scope and a function generator to machine and compare the VP patches and
>>RTAI under very high stress. This certainly would certainly be food for
>>thought for everyone involved.
> 
> 
> And the scope does what you argued in a LKML thread and what I asked for
> ?
> "And this has been demonstrated mathematically/algorithmically to be
> true 100% of the time, regardless of the load and the driver set?"
> 
> That's why I was saying "blah". Provide the things yourself to prove
> your point, before asking others to provide them.
> 
> Here are the LibeRTOS/KURT (2.4) numbers on the same machine (300MHZ
> Pentium) compared to RTAI in a long run test:
> 
> IRQ latency for a self contained IRQ
>                 RTAI            LibeRTOS
> No Load         7,8 usec        7,8 usec 
> ping -f         8,6 usec        9,8 usec 
> hackbench       12,6 usec       11,8 usec 
> hbench + ping-f 13,6 usec       13,4 usec
> 
> Userspace latency
>                 RTAI LXRT       LibeRTOS
> No Load         18,92 usec      20,45 usec 
> ping -f         19,10 usec      21,14 usec 
> hackbench       33,10 usec      35,16 usec
> hackb + ping -f 34,56 usec      35,40 usec
> 

What version of RTAI please?

Paolo.





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