Re: [FFADO-devel] [MOTU] r903 to r918

[Jonathan W. <jw...@ph...>]

Hi guys

> Libffado-svn903 seems to be the last working revision for MOTU.
> r904 introduces a stability problem: the sync is immediately lost with a
> lot of xruns (with my ardour test session).

I worked with r908 over the weekend and was largely successful after I fixed
a typecast problem in CycleTimerHelper.cpp (see earlier post for details).
Again though, it wasn't tested under heavy load.

> r905 introduces a lot of glitches.

I wonder whether at least some of the glitches were caused by the typecast
problem.

> r918 solves the stability problem but glitches are still there.

This is curious - I can't immediately see anything in r905 which would have
been addressed in r918.  However, I've only had a quick look at the commits
so there may be some subtle issue.

> I didn't have time to test r906 to r917 individually but I don't think it
> will tell more.

Probably not.

> libffado-svn903 definitely works well: I managed to play my test ardour
> project with 2x256 buffers with ISOHANDLER_PER_HANDLER_TREAD set to 1.
> 2x128 seems to be stable with all plug-ins deactivated (this is not fully
> tested; it is probably ok with a few plugs activated).

This is good news - at least up to r903 we were heading in the right
direction.

> Note that the shutdown but reappeared on this revision (perhaps already
> fixed in the last svn).

Please see if r928 is any better in this regard.  I noticed shutdown issues
in r908 and the changes in r928 fixed them for me.

> The stability seems to depend on the proc charge. The more I activate
> plug-ins, the less the driver is stable (lose the sync more often). 
> Moreover ISOHANDLER_PER_HANDLER_TREAD is a key parameter.
> 
> There seems to be a thread (RT?) related issue, at last on my system.

Over to Pieter. :-)

> > what kernel are you running? and are you on a single cpu or a
> > multi-cpu/core?
> 
> Linux 2.6.23-rc2-rt2 with the ieee1394 patch v474 compiled for single cpu
> and complete preemption.

I should point out that my current testing kernel is kernel.org 2.6.24 with
the "low latency desktop" setting.  Recently I've steered away from the RT
kernels since they haven't played well with reiserfs and xfs on my system of
late.

Regards
  jonathan