[Tremor] Implementing Tremor on low-end ARM

[Nicholas Vinen]

Replying to myself again.

Well, I've done some further investigations into Tremor's memory
allocation. I have redirected each different call to
malloc/calloc/realloc/free into a separate function. I've also set it up
so that I can just change one #define and it will redirect them all back
to the standard allocation functions. Thus this could possibly become a
standard part of Tremor (if people feel it's worthwhile). The idea is
that I can (a) see what's being allocated where and how much and (b)
theoretically write different allocation functions for each type of
buffer required.

The more I think about this the more I think that I will be able to get
away with dedicating a certain portion of memory to certain things (data
buffers, "dectable", code books, etc.) and just split up this memory
into chunks as required by Tremor. i.e. it will allocate them all in one
go, then probably free them all when playback is finished, so there's no
need for any kind of intelligent allocation. Some other things may be
more dynamic but this could be handled by giving them "large enough"
chunks (possibly more than they ask for) in order to cover the maximum
that will be asked for.

If/when I come up with a sensible static memory allocation strategy I'll
report on it. For now here is what the allocations look like for playing
back what I would consider a fairly ordinary Ogg Vorbis file. I note
that it seems to be allocating an awfully large numer of buffers - I
wonder if this could be reduced somewhat?

_ogg_calloc_sync 28
_ogg_calloc_bufstate 16
_ogg_calloc_stream 76
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_ref 16
_ogg_malloc_ref 16
_ogg_malloc_ref 16
_ogg_calloc_info 52
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_ref 16
_ogg_malloc_ref 16
_ogg_malloc_ref 16
_ogg_malloc_ref 16
_ogg_calloc_vendor 30
_ogg_calloc_comments 20
_ogg_calloc_commentlens 20
_ogg_calloc_comments2 12
_ogg_calloc_comments2 12
_ogg_calloc_comments2 28
_ogg_calloc_comments2 15
_ogg_calloc_bookparam 2816
_ogg_malloc_dectable 14
_ogg_malloc_dectable 126
_ogg_malloc_dectable 126
_ogg_malloc_dectable 508
_ogg_malloc_dectable 62
_ogg_malloc_dectable 380
_ogg_malloc_dectable 32
_ogg_malloc_dectable 62
_ogg_malloc_dectable 308
_ogg_malloc_dectable 32
_ogg_malloc_dectable 62
_ogg_malloc_dectable 308
_ogg_malloc_dectable 30
_ogg_malloc_dectable 14
_ogg_malloc_dectable 1020
_ogg_malloc_dectable 126
_ogg_malloc_dectable 508
_ogg_malloc_dectable 62
_ogg_malloc_dectable 380
_ogg_malloc_dectable 62
_ogg_malloc_dectable 380
_ogg_malloc_dectable 32
_ogg_malloc_dectable 62
_ogg_malloc_dectable 308
_ogg_malloc_dectable 32
_ogg_malloc_dectable 62
_ogg_malloc_dectable 308
_ogg_malloc_dectable 198
_ogg_malloc_dectable 192
_ogg_malloc_dectable 1440
_ogg_malloc_dectable 200
_ogg_malloc_dectable 528
_ogg_malloc_dectable 320
_ogg_malloc_dectable 480
_ogg_malloc_dectable 344
_ogg_malloc_dectable 48
_ogg_malloc_dectable 672
_ogg_malloc_dectable 480
_ogg_malloc_dectable 896
_ogg_malloc_dectable 1760
_ogg_malloc_dectable 672
_ogg_malloc_dectable 672
_ogg_malloc_dectable 96
_ogg_malloc_dectable 198
_ogg_malloc_floorparam 8
_ogg_malloc_floortype 2
_ogg_calloc_floor1 36
_ogg_malloc_partition 6
_ogg_malloc_class 44
_ogg_malloc_postlist 38
_ogg_malloc_fwdindex 19
_ogg_malloc_loneighbor 17
_ogg_malloc_hineighbor 17
_ogg_malloc_fwdindex 19
_ogg_free_fwdindex
_ogg_calloc_floor1 36
_ogg_malloc_partition 8
_ogg_malloc_class 55
_ogg_malloc_postlist 58
_ogg_malloc_fwdindex 29
_ogg_malloc_loneighbor 27
_ogg_malloc_hineighbor 27
_ogg_malloc_fwdindex 29
_ogg_free_fwdindex
_ogg_malloc_residueparam 56
_ogg_malloc_stagemasks 10
_ogg_malloc_stagebooks 80
_ogg_malloc_stagemasks 10
_ogg_malloc_stagebooks 80
_ogg_malloc_mapparam 40
_ogg_malloc_coupling 2
_ogg_malloc_submaplist 2
_ogg_malloc_coupling 2
_ogg_malloc_submaplist 2
_ogg_malloc_modeparam 4
_ogg_malloc_offsets 16
_ogg_malloc_serialnos 4
_ogg_malloc_dataoffsets 8
_ogg_malloc_pcmlens 16
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_ref 16
_ogg_calloc_stream 76
_ogg_free_stream
title=Donna
artist=10cc
album=The Very Best of 10cc
tracknumber=01

Bitstream is 2 channel, 44100Hz

Decoded length: 7776300 samples
Encoded by: Xiph.Org libVorbis I 20050304

_ogg_calloc_dspstate 76
_ogg_malloc_dsp_work 8
_ogg_malloc_dsp_mdct 8
_ogg_calloc_dsp_work2 4096
_ogg_calloc_dsp_mdct2 2048
_ogg_calloc_dsp_work2 4096
_ogg_calloc_dsp_mdct2 2048
Playing raw data 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz,
Stereo
_ogg_malloc_buffer 16
_ogg_malloc_bufdata 1024
_ogg_malloc_ref 16
_ogg_malloc_ref 16

Aborted by signal Interrupt...