[ardour-users] [Fwd: Re: Is 64 bit dual core supported and stable yet?]

[Joel White]

Fernando Lopez-Lezcano wrote:

>On Fri, 2005-12-02 at 11:20 -0500, George Chan wrote:
>  
>
>>I finally decided on what system to build, that included a dual core
>>Athlon.  
>>
>>Then I received this email.
>>
>>So, I guess, that for now, it would be better to have a Dual CPU Single
>>Core Opteron system?
>>
>>What do you think?
>>    
>>
>
>The latest patch for realtime preemption from Ingo Molnar does not use
>the TSC for internal timing in the kernel in the case of the dual core
>Athlon X2 cpus (2.6.14-rt12). So the kernel problems do not happen (in
>my case I experienced sporadic key repeat problems and random temporary
>activations of the screensaver). 
>
>A patch is needed for Jack so that it does not use the TSC for timing
>with those cpus, some stuff has been posted to the jackit-devel list but
>no definite patch is yet on CVS. 
>  
>
I am currently running stock 2.6.14 with the 3800+ X2 (that's me, 
below).  If I set the smp_affinity of my sound card to one processor, 
the "delay of xx usecs exceeds.." messages virtually disappear.  Without 
that, they pop up regularly, with increasing delay times.

As a test, I just got through recording 55+ min of 8 tracks (-r 44100 -p 
64 -n 2, duplex) before ardour halted with an xrun and "delay.." error.  
Is it likely that this is still due to the problems mentioned above and 
in the jackit-devel list?  I don't see any other reason for this 
particular xrun/delay (I wasn't doing anything to stress the system).  
Any ideas would be appreciated.  (I tried running with acpi=off, as well 
as building the kernel without power management as Paul suggested to me, 
but the system hung up, so I'm back to acpi).

Thanks,

Joel

>So things are getting there...
>-- Fernando
>
>  
>
>>------- Forwarded Message --------
>>From: Paul Davis <paul at linuxaudiosystems.com>
>>Reply-To: paul at linuxaudiosystems.com
>>To: Joel White <cv223 at comcast.net>
>>Cc: ardour-users at lists.ardour.org
>>Subject: Re: [ardour-users] Is 64 bit dual core supported and stable
>>yet?
>>Date: Tue, 29 Nov 2005 09:34:28 -0500
>>
>>On Mon, 2005-11-28 at 23:15 -0500, Joel White wrote:
>>    
>>
>>>Even thought the results are good so far, I still get occasional xruns like:
>>>
>>>**** alsa_pcm: xrun of at least 118.867 msecs
>>>(this particular xrun interrupted a recording with my band, which is 
>>>_very_ bad! I was even running capture only and with a longer period, 
>>>just to be sure xruns wouldn't happen!)
>>>
>>>and the odd:
>>>
>>>delay of 1131462.000 usecs exceeds estimated spare time of 5606.000; 
>>>restart ...
>>>(this type of error comes mostly when audio connections change, but also 
>>>at other times, although the delay isn't usually quite so long)
>>>
>>> From my understanding, both of these time periods indicate something 
>>>very wrong (an xrun of 118+ msecs?? a delay of 1.13+ _sec_?!?!), but I 
>>>haven't been able to track them down, yet.  I've run Ardour recording 8 
>>>      
>>>
>>this is caused by a design fault in AMD's dual core offerings. they have
>>already made it clear that future designs will rectify the problem.
>>there is a slowly evolving discussion on jackit-devel to try and decide
>>what to do about it.
>>
>>--p
>>    
>>
>
>
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>  
>