Re: 2.6.16-rt1

From: K.R. Foley
Date: Wed Mar 22 2006 - 11:07:50 EST


K.R. Foley wrote:
> Ingo Molnar wrote:
>> * K.R. Foley <kr@xxxxxxxxxx> wrote:
>>
>>> Sorry I have been onsite and completely buried today. Am running an
>>> initial test on both UP and SMP now with 2.6.16-rt1. UP doesn't look
>>> bad at all. SMP on the other hand doesn't look so good. I will give
>>> -rt4 a spin when these are done.
>> thanks for the testing - i'll check SMP too.
>>
>> Ingo
>>
> OK. On my dual 933 under heavy load I get the following with 2.6.16-rt4
> and I get tons of missed interrupts. Running 2.6.15-rc16 I get a max of
> 88usec with most falling under 30usec. On my UP AthlonXP 1700 I get a
> max of 19usec with 2.6.16-rt4 under load. What sort of results do you
> see on SMP?
>

Found something interesting. Having Wakeup latency timing turned on
makes a HUGE difference. I turned it off and recompiled and now I am
seeing numbers back in line with what I expected from 2.6.16-rt4. Sorry,
but I had no idea it would make that much difference. I don't have a
complete run yet, but I have seen enough to know that I am not seeing
tons of missed interrupts and the highest reported latency thus far is
61 usec.

--
kr
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