[ardour-dev] Ancient history? - Problem identified

[Jan Depner]

Just curious but are you both running NVIDIA graphics cards with the
accelerated driver?

Jan

On Thu, 2004-11-11 at 11:52, R Parker wrote:
> Hi Joel,
> 
> --- cv223 at comcast.net wrote:
> 
> > A few days ago I posted the following message about
> > tracking down xruns using Ardour to record to a SCSI
> > Raid0.  At the end of the message, I asked whether
> > anyone had any ideas about why commenting out a
> > single line in streamview.cc (which at the very
> > least eliminates updating the "progress" rectangles
> > during recording) completely eliminates my xrun
> > problem, in a rather dramatic fashion (dozens of
> > xruns per min to none).  Since I got a goose egg in
> > response, I thought I would try again because I've
> > run out of things to test and don't know where to
> > look next.  
> 
> I took note of your first message. It's certainly an
> interesting discovery. 
> 
> > Basically, how can display updates in Ardour during
> > recording cause xruns with writes to the hard
> > drives?
> 
> I'm not a programmer but we have to imagine the
> function operates outside the realtime threads. If
> that's correct and all is well within the code, then
> Ardour isn't the cause but does trigger the symptom.
> 
> It would seem to indicate xruns caused by the video
> driver but you have narrowed it down to a hardware
> scsi raid event where the problem occurs.
> 
> Being pretty clueless, perhaps all I'm doing is trying
> to add some life to your thread. Incidentally, the
> region drawing code was written by Jesse Chappel--I
> think. If you do IRC, he can often be found on
> freenode.net #ardour.
> 
> Sorry I can't be very helpful, more sorry than you
> know because I also run hardware raid and have xrun
> problems.
> 
> ron
> 
> > Since this problem doesn't seem to be common, it
> > seems that it has more to do with my system/hardware
> > configuration than with Ardour/jack.  But what, I
> > don't know.
> > 
> > Any suggestions would be greatly appreciated. 
> > Thanks for your time.
> > 
> > Joel
> > -------------- Original message -------------- 
> > 
> > > (Note that I didn't write "Problem solved" - I
> > don't know how to solve 
> > > it, besides a hack described below) 
> > > 
> > > About a week ago, I posted a message asking about
> > possible reasons why 
> > > xruns seen using 0.9beta11.2 when recording to a
> > SCSI Raid0 went away 
> > > with 0.9beta12 (on a 2.4.23 kernel). Paul took
> > pity on my poor, 
> > > tormented soul and let me have cvs access (thanks
> > again, Paul!) so I 
> > > could try and track down the problem. I went
> > through a number of old 
> > > cvs versions by the dates of "CVS commit" messages
> > to the ardour-dev 
> > > list (not sequentially - I don't have _that_ much
> > time!) and found the 
> > > smoking gun to be on May 7, 2004, when Jesse
> > Chappell committed code to 
> > > put waveforms into regions while recording. That
> > code pointed out where 
> > > the problem was. 
> > > 
> > > To make a long story somewhat shorter, it turns
> > out that on my system, 
> > > updating the regions during recording (even with
> > "Follow playhead" 
> > > turned off) generates xruns when the SCSI Raid is
> > written to (i.e., 
> > > xruns occur when the drives chirp). Specifically,
> > if I comment out line 
> > > 700 in streamview.cc (this is in routine
> > StreamView::update_rec_box() 
> > > in 0.9beta19): 
> > > 
> > > // gtk_canvas_item_set (rect, "x2", xend, NULL); 
> > > 
> > > and run Ardour with the Display Option "Show
> > waveforms while recording" 
> > > turned off, I get no (zero!) xruns while recording
> > to the SCSI Raid, 
> > > where before I got > 25 per 1 minute of recording.
> > Of course, I don't 
> > > get the pinkish boxes growing across the screen,
> > but I can live with that. 
> > > 
> > > If I don't comment out that line, I get just as
> > many xruns on the newer 
> > > versions of Ardour as before - I hadn't tried
> > turning "Show 
> > > waveforms..." off before I started on my cvs
> > quest. I guess I thought 
> > > the waveforms during recording were too cool. 
> > > 
> > > Turning on the "Show waveforms..." still generates
> > about 3 xruns per 
> > > minute of recording, so I still don't know what's
> > going on there (other 
> > > gtk canvas access, perhaps?). Also, running under
> > the 
> > > 2.6.9-rc2-mm4-VP-S7 kernel still generates a
> > handful of xruns per minute 
> > > on either Raid or IDE drives even with the above
> > hack, so something 
> > > different still seems to be happening with that
> > kernel. I'll stick with 
> > > 2.4.23 for now. 
> > > 
> > > If anybody has any ideas about what may be going
> > on (how gtk canvas 
> > > access + SCSI Raid writes = xruns), I'm still
> > curious. Also, I'm 
> > > willing to try additional tests, if it would be
> > helpful. 
> > > 
> > > BTW, this is with gtk+ version 1.2.10. 
> > > 
> > > Thanks for your time, 
> > > 
> > > Joel 
> > > 
> > > 
> > > 
> > > _______________________________________________ 
> > > ardour-dev mailing list 
> > > ardour-dev at lists.ardour.org 
> > >
> >
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> >
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> 
> 
> 
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