17 Aug
2011
17 Aug
'11
6:39 p.m.
The only thing that struck me is that I'm under the impression that
memory allocation and deallocation, even by the GUI thread, can cause
pauses to the whole process. Hence, a threading model is not enough
for decoupling memory allocation pauses. Can anyone comment on
whether this is true? My impression is that at least a new or malloc
can stimulate a brk()/sbrk(), which will generate a page fault. Not
sure about deallocations.
Of course, a pre-allocated object pool can deal with this.
Steve
On Sat, Aug 6, 2011 at 5:57 AM, Florian Paul Schmidt
<mista.tapas(a)gmx.net> wrote:
On 08/06/2011 04:23 AM, Florian Paul Schmidt wrote:
Hi,
during the process of writing a new small jack sampler which fits my
workflow I came up with this little scheme to solve the UI/engine decoupling
problem. For the purpose of spreading the idea or alternatively getting
answers about how it's broken and sucks I decided to write a little article
describing it..
http://178.63.2.231/~tapas/wordpress/?page_id=45
The (largely unfinished and unusable) sampler project is here:
https://github.com/fps/jass
Let me have it..
I guess I should mention the approach in a nutshell. Assiging a new
generator (that plays a sample) to the first element of a std::vector of
generators in the engine the UI would do e.g.:
engine.commands.write(assign(engine.gens->t[0], p));
where assign() is a function that builds a functor that dassigns the right
argument to the left, p is a
boost::shared_ptr<disposable<generator> >
or with typedef
disposable_generator_ptr,
gens is a
boost::shared_ptr<disposable<std::vector<boost::shared_ptr<generator> >
> >
or with typedefs:
boost::shared_ptr<disposable<std::vector<disposable_generator_ptr> >
or even shorter
disposable_generator_vector_ptr
Replacing the whole vector of generators with a new one (after e.g. loading
a complete setup) wood look like:
engine.commands.write(assign(engine.gens, v);
where v would be a disposable_generator_vector_ptr.
Just calling the set_sample member of a generator would look like this:
engine.commands.write(&generator::set_sample, engine.gens->t[0]->t, s)
where s is a disposable_sample_ptr..
The ->t thingies show up, because every object is wrapped in a disposable<T>
which has a member t that is the "payload"..
I wonder if there's an even more elegant approach to cook down the verbosity
a bit.. What you get, though, for the verbosity is the ability to call
almost every member of every object in the engine's collection of objects
without writing extra classes to define a command.. Such is the power of
boost::bind and boost::function..
Flo
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev(a)lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-dev