Subject: Re: [linux-audio-dev] News about sequencers (not my own though!)
From: jfm3 (jfm3_AT_acm.org)
Date: ma tammi 24 2000 - 12:44:57 EST
Benno Senoner wrote:
> 1ms precision is pretty critical ... , I wouldn't do anything other than
> using C code which avoids to call any "non-deterministic" systemcalls.
> ( disk i/o , etc).
>
> Using an interpreted language scares me because it may be much slower than C
> and in order to guarantee real-time behaviour you must assume that the
> interpreter doesn't make any of these non-deterministic syscalls in the
> interpreting loop. (plus it has to be SCHED_FIFO / SCHED_RR ).
>
> Therefore if you want "hard-realtime" and are paranoid as David Olofson says ,
> go with C/C++ , else you have to trust 100% your interpreter, and very often
> interpreters aren't designed with realtime in mind.
I agree. The problem is when I want "real time" sequencing with "logic" (not
Logic(TM)). If I want to give a command to my sequencer like "in this given
MIDI pattern, reduce all CC#11's greater than 72 to 72." my only hope is with a
little extension/command language. It's a hard problem and any solution is
impressive.
Keykit does an admirable job of getting language interpretation done quick enough
to do real music. It isn't an ideal language, but it certainly is useful, and if
nothing else is proof of concept. I don't think it qualifies as "hard" real
time, but yet it is still a practical tool.
In my mental wanderings on the subject, I came across a good site that addresses
a lot of developers concerns regarding garbage collection, including real time
stuff. Did you know that in practically every implementation malloc() or
::operator new() is not guaranteed to finish in bounded time?
http://www.harlequin.com/products/st/mm/
This archive was generated by hypermail 2b28 : pe maalis 10 2000 - 07:23:26 EST