[PlanetCCRMA] (Fwd) gak

DA. Forsyth steampipe at iwr.ru.ac.za
Mon Nov 12 23:51:01 2007

On 12 Nov 2007 at 11:56, Fernando Lopez-Lezcano murmured decisively:

Hi Fernando

> > so what happens?   Sunday morning I do a quick 'record 8 channels' test 
> > and jack goes nuts with xruns.  check, no settings have changed.  fiddle 
> > around for a looong time before discovering that setting 'priority' to 50 
> > instead of 0 gets it working (why the change since last year). 
> Did you do any package upgrades in between? 


> Installed manually any "critical" software? (jack/ardour/etc). 

no.  I try not to do any custom software at all.

> There have not been upgrades for fc5 in Planet CCRMA for a long time, so
> nothing should change. 

that's what I thought (-:

> The priority setting in qjackctl overrides the default in jackd, "0"
> means do not override. Unless jackd has been manually updated its
> priority should not have changed - and it is set in the build process to
> a value that is right for the Planet CCRMA kernel. Weird. 

any idea what that value is?

> [BTW, which kernel are you running? 'uname -r' to know].

2.16.something RT SMP... machine is at home right now so I cannot check

> >  right on!  
> > ....  do a trial with software RAID between the 2 disks, (appears to) 
> > works ok, so lets go... lets go record the band
> Is this true linux software raid? Or are you using ardour's "raid"
> facility? 

ardours raid.

> > things, and each song is different.  and I'm still getting 'your disk is 
> > too slow' during playback, now and then.  I think it is the big files. 
> Do you have a lot of overlapping regions? 

No.  I record linearly without overlapping regions.

> If so, they _all_ "play" (if I understand things correctly). You should
> disable the regions that you are not using if you have a lot of tracks.
> Otherwise the disk will not be able to keep up. 
> I don't know why ardour is doing what it is doing in your case. It may
> be worth asking in the ardour-users list (with a preface saying you are
> still using 0.99.3). 

I was on ardour IRC channel yesterday and was advised, rightly, to look at 
'hdparm'.   discovered damn slow disk access and was able to double it by 
enabling 32bit access mode.  seems my SATA drives are being considered as 
IDE drives by FEdora, probably because the BIOS is in emulation mode of 
some kind.   

This was a big fix.  no xruns, no timeouts.  basic solid performance from 
17:30 to 02:30 with only one message about 'cannot read peak information' 
while I was zooming in/ouot with multiple steps (keyboard shortcuts) 
without waiting for ardour to catch up.  that did not stop the circus and 
fixed itself.

a keybinding that would be really handy is 'zoom to current range'

> > but the hardware is doing 48000.   I tried deleteing ~/.jackdrc but the 
> > hardware still went to 48000.   how does one actually change it?
> Normally in envy24 based cards just changing the sampling rate in
> qjackctl is enough. Is your card running as a master? Or is it slaving
> to something external? (which could force it to run at 44.1K). 

it is master, I don't anything else it could plug in to (-:

> What happens if you exit all the audio programs and then do, from the
> command line:
>   jackd -R -d alsa -d hw -r 44100

I'll try that next week, leaving town in a couple of hours for the rest of 
this week, one of the reasons I got to bed about 02:30 after mixing 3 
songs and time aligning regions on 4 which took ages.  another 3 to go, 
for the CD, and a slightly different mix for the DVD....

and then I was confused by not actually getting ardour list email for a 
bit, but found them in the spam folder (along with ~600 other emails)

David                       http://iwr.ru.ac.za/~iwdf/
If you receive email saying "Send this to everyone you know",
           PLEASE pretend you don't know me.