Subject: Re: [linux-audio-dev] MuCoS, Glame, API Issues
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: to maalis 09 2000 - 11:17:22 EST
>> >No, the API looks very strange to me, especially the "host controlled"
>> >LADSPA_Data * DataLocation per connection!? what is this for (see
>> >alexanders question below, too)??
>>
>> so that the host can improve cache performance by reusing data
>> buffers. if you leave buffer allocation to the plugins, the chances
>> are that you will trash the cache every time you call a new one. given
>> that people have noticed this effect in Csound quite easily (if you
>> reuse variable names for multiple purposes, a Csound instrument
>> typically runs noticeably faster), I feel confident in pointing out
>> that this is a very real effect.
>
>How does host controlled allocation work, if you have sample generating
>plugins? How does host controlled allocation work, f.i. on a resample
>plugin? I dont see the point - if allocation is dedicated to the plugins
>one can forward the buffer and do modifications in-place in every plugin,
>this is more cache friendly than for each plugin having a seperate buffer
>to read from and to write to.
"host controlled allocation" doesn't specify any particular way of
allocating buffers. it describes the division of responsibility. if
plugins allocate their own buffers, their actions may not be optimal
given the current global situation. if the host does it, it can
(presumably) make the best decisions about how to allocate buffers and
pass them around. whether it allocates one per plugin, makes them all
share, or whatever else, is invisible to the plugins and should be
assumed to be "taken care of" by plugin writers.
VST certainly works this way.
--p
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