Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.30-2

[Rui Nuno Capela]

Ingo Molnar wrote:
>
> Rui Nuno Capela wrote:
>
>> > great. I now suspect that some of the xrun problems Rui was observing
>> > on -RT kernel could be (positively) affected by these fixes too.
>> >
>>
>> Just made some test-runs with RT-V0.7.30-2, with my jackd-R +
>> 8*fluidsynth benchmark on my laptop (P4/UP), and the results don't
>> seem to be eligible to the hall of fame, at least when compared with
>> RT-0.7.7 as the ones I last posted here a few weeks ago.
>>
>> I hate to say this, but the XRUN rate has increased since RT-0.7.7,
>> and the maximum scheduling delay reported by jackd has also degraded
>> to 1000 usecs (was around 600 usecs).
>
> well, life would be too easy if two bugs were fixed at once ;) These
> were nodebug runs, right? Could you give me a description of the precise
> commands of how you started jackd and fluidsyth (and their versions) -
> so that i could try to reproduce & debug your setup. It is certainly a
> complex scheduling scenario.
>
> (perhaps with a link to the .sf2 and .mid files you used, if they are
> public - or whether it's fine if i use the VintageDreamsWaves-v2.sf2
> sound-fonts that comes with fluidsynth plus a random .mid file from the
> net?)
>

These are the command-lines of my test suite:

  jackd -R -dalsa -dhw:0 -P20 -r44100 -p64 -n2 -S -P &
  fluidsynth -s -i -a jack -j -o jack.audio.id=fluid1 -o shell.port=9800
ct4mgm.sf2 &
  fluidsynth -s -i -a jack -j -o jack.audio.id=fluid2 -o shell.port=9801
ct4mgm.sf2 &
  .
  .
  .
  fluidsynth -s -i -a jack -j -o jack.audio.id=fluid8 -o shell.port=9807
ct4mgm.sf2 &


Versions are:

  jack 0.99.10cvs
  fluidsynth 1.0.5


>> OTOH, there's another thing: I don't seem to be able to build an
>> initrd image under the latest RT kernels. Something related to the
>> loopback device. When trying to run mkinitrd it stalls, somewhere
>> under this process:
>>
>>   mount -t ext2 /root/tmp/initrd.img /root/tmp/initrd.mnt -o loop
>
> Do you know when this started, roughly?
>

Not sure, but the first time I've noticed it was on RT-0.7.29-2 and that
was purely by chance. Problem is that I've been building the RT kernels
under a non-RT stock kernel, so I can't say how long or when it all
started exactly. I remember however that this is a revisited issue,
thought.

Cheers.
-- 
rncbc aka Rui Nuno Capela
rncbc@xxxxxxxxx

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