[linux-audio-dev] A sequencer example

[mlang]

Lee Revell <rlrevell at joe-job.com> writes:

> On Sun, 2006-01-15 at 14:23 +0100, mlang wrote:
>> Chris Cannam <cannam at all-day-breakfast.com> writes:
>> 
>> > On Sunday 15 Jan 2006 11:12, Florian Schmidt wrote:
>> >> If you want to use alsa_seq's queues to schedule events for delivery
>> >> at a later time, you probably might have a look at rosegarden.
>> >
>> > There's a file base/test/seq/generator.c in the Rosegarden source tree 
>> > that does basically what was described using the sequencer queue.  It 
>> > does however schedule in real-time rather than beats (and so does 
>> > Rosegarden itself).
>> >
>> > http://cvs.sourceforge.net/viewcvs.py/rosegarden/base/test/seq/generator.c?view=markup
>> 
>> Pretty intersting, I just ran this and noticed it (the diff between
>> queue and gettimeofday time) drifts about 70 usecs per second.  Is this
>> normal expected behaviour, or another reason to hate the day I decided to buy
>> a X2 CPU?
>> 
>> P.S.: ANyone got any hard facts on the TSC SMP issues?  2.6.15
>> is definitely worse for me than 2.6.14, things that used to work just dont anymore.
>> 
>
> Yes, the TSC is useless on these machines, but the kernel can work
> around it.  You need JACK patched to use clock_gettime() for
> jack_get_microseconds.

THis doesn't make sense to me, either the kernel can work around it
properly *OR* we have to patch userland.

-- 
CYa,
  Mario