[DUG] Memory allocation speed

[Rohit Gupta]

  I think that because your chunk size is constant, the memory manager 
just returns previous blocks to you.  So fragmentation does not occur.

On 24/09/2010 01:52, Ross Levis wrote:
>
> Just wanted some opinions on how bad a practice this is!
>
> I have written a media player which uses a DLL to decode audio files.
>
> The DLL opens an MP3 file for example, and sends back decoded raw 
> audio, usually in chunks of 4608 bytes (~20ms), but could be a 
> different size.
>
> I need to buffer this audio data for around 5 seconds (1 MB).
>
> Rather than writing a complicated circular buffer which feeds in one 
> end and is taken from the other, I decided to simply allocate memory 
> for each new chunk and store a link from one memory location to the 
> next.  The oldest buffer is read and memory released.
>
> So there is roughly 1 new memory space being allocated and 1 being 
> destroyed every 20ms or so, with around 200 chunks being stored at any 
> one time.
>
> I'm using D7 with the FastMM4 memory manager.
>
> It is working very well with very little CPU usage at all, which I was 
> surprised at.  I've always been under the impression that allocating 
> memory is a slow process.
>
> Thoughts?
>
>
>
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-- 
Regards

*Rohit Gupta*
B.E. Elec., M.E., Mem IEEE, Member IET
Technical Manager
Computer Fanatics Ltd

*Tel *4892280
*Fax *4892290
*Web *www.cfl.co.nz
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