[gst-embedded] How to reduce gstreamer library size & startuptime

[Nicholas Hannah]

Hi All,

I have ported Gstreamer to a small embedded OS.

I statically link all plugins that I need for a particular pipeline  
and explicitly call their initialisation routines. This means I  don't  
need to scan for plugins or run any dynamic module loading code. I  
haven't done any proper tests to see how this reduces running time or  
code size but it is noticeably quicker to start up (especially when  
debugging is turned on) than a standard install.  Let me know if  
anyone is interested in how I did this.

As an aside I think that static linking is a good option for embedded  
systems because:

1) small OS's don't always (usually?) have a dynamic loader or  
dlopen(), dlsym() etc,
2) as mentioned earlier, in embedded environments new plugins probably  
won't be installed very often, so dynamic module loading is less useful,
3) switching off all dynamic loading code will result in overall  
smaller code size and better performance.

In my opinion it would be nice if Gstreamer had better support for  
static linking.

Regards,

Nick


> Hi,
>
> On Thu, 2008-02-28 at 10:28 +0100, Wouter Cloetens wrote:
> > On Thu, Feb 28, 2008 at 05:23:40PM +0800, Zhao Liang-E3423C wrote:
> > > 1. disable many unused features
> > > 2. disable debug/trace
> > > 3. use binary registry or not use registry
> > > 4. disable runtime check
> >
> > Has anyone considered statically linking plugins? I suspect that  
> would
> > be a rather big change, but you would win on startup time, in memory
> > consumption and in runtime CPU usage.
>
> Most likely, the biggest time consumption in initialization is
> checking for modifications of plugins (scannning directories,  
> looking at
> timestamps, loading them if changed, ....).
>
> We *could* add an option to NOT do that scanning at startup (if an
> environment variable is set when running for example) and just load  
> the
> available registry.
> In embedded environments you are most likely not installing new
> plugins very often, so this checking is almost never used but might  
> cost
> a lot.
>
> You are of course then left with the cost of loading the actual
> plugins required by the application afterwards, but that's after
> initialization.
>
> Has anybody done some timing to see how long gst_init() takes ?
>
> Edward
>
> >
> > bfn, Wouter
> >
> >  
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> -- 
> Edward Hervey <edward.hervey at co...>
> Collabora Multimedia
>>
>