29 May
2003
29 May
'03
8:58 p.m.
"jacob robbins" <jrobbins(a)newyorkmusicunion.com> writes:
I'm a little green at time measurement facilities
available in linux,
In my host, I would like to be able to measure how much time each
individual LADPSA plugin takes. Assuming I do realtime work with the
smallest buffer sizes my system can handle, what options are available
to me to measure time on this small scale? I know that the typical
system calls time and gettimeofday have resolution of 10 ms, which is
too big for this purpose. Is there any way to do this? Is there a
high-res time howto?
I've been using jack_frame_time() for tracing audio threads in a JACK
client. It works quite well. Basically you get a running frame
counter (unsigned long) which can be used to compute the difference
from an earlier measurement. The resolution depends on the JACK
sample rate, which is typically either 1/48000 sec or 1/44100 sec.
If you're using JACK anyway, this is an easy solution.
There are lots of other facilities available. I'm sure others will
explain their advantages and disadvantages. :-)
--
Jack O'Quin
Austin, Texas, USA