Subject: Re: [linux-audio-dev] plugin questions
From: David Olofson (audiality_AT_swipnet.se)
Date: su loka 10 1999 - 16:34:46 EDT
On Sun, 10 Oct 1999, Paul Barton-Davis wrote:
[...]
> crossing the user/kernel boundary is too expensive for distributing
> events which the kind of response we want. the communication system
> needs to reside in user-space, IMHO.
User/kernel "switches" are not nearly as expensive as real context
switches. This is not Windows... ;-)
> the sequencer fits into this system because of the abstraction it
> provides of the existing (currently just MIDI-related) device drivers,
> turning them into subscribable event queues.
>
> but having to cross into the kernel every time we want to deliver or
> receive an event is not the way to go, i think.
Once every time you want to end a cycle. That's why I designed the
inline memory allocator. If you set up a thread to wake up, get the
current time, and then send some out-of-band events rather frequently,
then you're already wasting orders of magnitude more on context
switching than the cost of a kernel call. (Unless I completely
missunderstood the kernel call vs. context switch discussion on
l-k...)
//David
·A·U·D·I·A·L·I·T·Y· P r o f e s s i o n a l L i n u x A u d i o
- - ------------------------------------------------------------- - -
·Rock Solid David Olofson:
·Low Latency www.angelfire.com/or/audiality ·Audio Hacker
·Plug-Ins audiality_AT_swipnet.se ·Linux Advocate
·Open Source ·Singer/Composer
This archive was generated by hypermail 2b28 : pe maalis 10 2000 - 07:27:13 EST