30 Sep
2013
30 Sep
'13
3:30 p.m.
On Mon, Sep 30, 2013 at 10:15:24PM +1000, Patrick Shirkey wrote:
I'm asking for additional suggestions on how to
authoritatively test this
combination and provide definitive results. I realise that it is a fairly
difficult question but it is part of a big push for wider adoption of open
source pro audio solutions so I hope that you will all feel it is worth
the effort to solve this problem too.
In a system such as the one you are testing latency is determined by
the amount of buffering, and nothing else. C-states shouldn't enter
in the picture as long as the CPU wakeup time is a small fraction of
a period (1.333ms in this case). If the wakeup time is too high, the
whole setup just fails. In other words, if you measure e.g. 100ms
of latency, that can only mean that somewhere along the pipeline
100ms of audio is being stored. It can't be the result of a CPU
being 100ms late - that would interrupt the signal instead.
Ciao,
--
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)