My attempt to multi-thread an audio talk-though program using batches of data

1
My attempt to multi-thread an audio talk-though
program using batches of data

• M. Smith
• Electrical and Computer Engineering
• University of Calgary,
• Smithmr _at_ ucalgary.ca

2
Laboratory 5 Done in C and C

• Stage 1 30
• Develop and investigate a multi-tasking system
  where the threads are free-running. Thread tasks
  are Sleep(time_task)
• Develop and investigate a multi-tasking system
  where the threads communicate through semaphores
  to control order of operation
• Stage 2 55
• Demonstrate and investigate turning an audio
  talk-through program into a multi-threaded
  system one point processed per interrupt
• Stage 3 15
• Demonstrate a batch processing system as a
  multi-threaded system
• Options
• Use SHARC ADSP-21061 boards (40 MHz) existing
  audio-libraries have not attempted
• Use Blackfin ADSP-BF533 boards (600 MHz)
  existing audio-libraries have been successful
  at home, but not here
• Use Blackfin ADSP-BF533 boards (600 MHz) using
  very simple, no frills, audio-talk though library
  surprising simple with 1 to 32 points being
  processed. Fails with 33 points. Code logic
  issue, not a timing issue as I can waste 25000
  cycles per block at 32 points

3
Implementing a multi-thread system-- Laboratory
5 Part B concepts
Collect 1 pts _at_44 kHz ? array1 Collect 1 pts _at_44 kHz ? array2 Collect 1 pts _at_44 kHz ? array3 Collect 1 pts _at_44 kHz ? array1 Collect 1 pts _at_44 kHz ? array2 Move array1 ? array4SimulateComplex Move array2 ? array5SimulateComplex Move array3 ? array6SimulateComplex Move array1 ? array4SimulateComplex Transmit N pts _at_44 kHz ? array4 Transmit N pts _at_44 kHz ? array5 Transmit N pts _at_44 kHz ? array6
4
Final ReadThread Single Point
5
Final ProcessThread Single Point
6
Final WriteThread Single Point
7
Read Thread ISR driven
8
Thread Status History ISR driven
9
Laboratory 5 Done in C and C

• Stage 1 30
• Develop and investigate a multi-tasking system
  where the threads are free-running. Thread tasks
  are Sleep(time_task)
• Develop and investigate a multi-tasking system
  where the threads communicate through semaphores
  to control order of operation
• Stage 2 55
• Demonstrate and investigate turning an audio
  talk-through program into a multi-threaded
  system one point processed per interrupt
• Stage 3 15
• Demonstrate a batch processing system as a
  multi-threaded system
• Options
• Use SHARC ADSP-21061 boards (40 MHz) existing
  audio-libraries have not attempted
• Use Blackfin ADSP-BF533 boards (600 MHz)
  existing audio-libraries have been successful
  at home, but not here
• Use Blackfin ADSP-BF533 boards (600 MHz) using
  very simple, no frills, audio-talk though library
  surprising simple with 1 to 32 points being
  processed. Fails with 33 points. Code logic
  issue, not a timing issue as I can waste 25000
  cycles per block at 32 points

10
Implementing a multi-thread system-- Laboratory
5 concepts
Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Collect N pts _at_44 kHz ? array3 Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Move array1 ? array4SimulateComplex Move array2 ? array5SimulateComplex Move array3 ? array6SimulateComplex Move array1 ? array4SimulateComplex Transmit N pts _at_44 kHz ? array4 Transmit N pts _at_44 kHz ? array5 Transmit N pts _at_44 kHz ? array6
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Read Handling 4 pointsNo-audio intention
just see if it will work test
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Process Handling 4 pointsNo-audio intention
just see if it will work test
13
Write Handling 4 pointsNo-audio intention
just see if it will work test
14
Nett Result
Not working as expected equal priority (5) on
each task We are obviously missing samples
15
Changing Priorities
Priorities ReadThread 3 -- obviously the
most critical ProcessThread 5 WriteThread 5
16
Different Priorities
Priorities ReadThread 3 -- obviously the
most critical ProcessThread 5 WriteThread 4
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No idle time available Optimize the code
Priorities ReadThread 3 ProcessThread
5 WriteThread 5
Priorities ReadThread 3 ProcessThread
5 WriteThread 4
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Implementing a multi-thread system-- Laboratory 5
Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Collect N pts _at_44 kHz ? array3 Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Move array1 ? array4SimulateComplex Move array2 ? array5SimulateComplex Move array3 ? array6SimulateComplex Move array1 ? array4SimulateComplex Transmit N pts _at_44 kHz ? array4 Transmit N pts _at_44 kHz ? array5 Transmit N pts _at_44 kHz ? array6
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Problem NOT coding what we intended
Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Collect N pts _at_44 kHz ? array3 Collect N pts _at_44 kHz ? array1 Collect N pts _at_44 kHz ? array2 Move array1 ? array4SimulateComplex Move array2 ? array5SimulateComplex Move array3 ? array6SimulateComplex Move array1 ? array4SimulateComplex Transmit N pts _at_44 kHz ? array4 Transmit N pts _at_44 kHz ? array5 Transmit N pts _at_44 kHz ? array6
20
Proper Code
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Net Result
TOTAL SYSTEM HANG BLOCKED SEMAPHORES
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Tried a number of things
Worked out which semaphore was blocking Different
priorities Different TIC times Better but
obviously missing cycles particularly write
23
Decided to tie WriteThread to interrupt as well
as ReadThread
24
Final Test Result
Seems to behaving as expected However when
changed MAXIMUM COUNT FOR READ / WRITE ISR
Semaphores status history changes This
could indicate that missing some interrupts
Could mean nothing interrupts asynchronous to
timer TICs
25
Could handle 800 waste times every 32 samples
plenty of time 50000 cycles
Inner loop 2 BUFFERLENGTHOuter loop
Wastetime (3 INNER) Total 13 Inner
loop BUFFER 32, waste time 800 Cycles around
800 64 50000
68K Blackfin
SHARC D0 (8) R0 (16)
R0 A0 (6) P0 (with a bit of MIPS) (6)
I0 (4)
I0 (16)
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Real life test -- small buffers

• Absolutely nothing
• However
• 4 audio connections in
• 6 audio connections out
• Got the correct connections
• Set buffer 1 worked first time
• Set buffer 32 worked first time

27
Larger buffers

• BUFFERSIZE 64 out of bsz memory error
• Fix .LDF file manually (GUI window works how?)

MEMORY mem_VDK_strt TYPE(RAM)
START(0xFFA00000) END(0xFFA00003) WIDTH(8)
mem_l1_code TYPE(RAM) START(0xFFA00004)
END(0xFFA0FFFF) WIDTH(8) mem_l1_code_cache
TYPE(RAM) START(0xFFA10000) END(0xFFA13FFF)
WIDTH(8) mem_EVT_all TYPE(RAM)
START(0xFF900000) END(0xFF900003) WIDTH(8)
mem_EVT_NMI TYPE(RAM) START(0xFF900004)
END(0xFF900007) WIDTH(8) mem_EVT_EVX
TYPE(RAM) START(0xFF900008) END(0xFF90000B)
WIDTH(8) mem_EVT_IRPTEN TYPE(RAM)
START(0xFF90000C) END(0xFF90000F) WIDTH(8)
mem_EVT_IVHW TYPE(RAM) START(0xFF900010)
END(0xFF900013) WIDTH(8) mem_EVT_IVTMR
TYPE(RAM) START(0xFF900014) END(0xFF900017)
WIDTH(8) mem_EVT_IVG7 TYPE(RAM)
START(0xFF900018) END(0xFF90001B) WIDTH(8)
mem_EVT_IVG8 TYPE(RAM) START(0xFF90001C)
END(0xFF90001F) WIDTH(8) mem_EVT_IVG9
TYPE(RAM) START(0xFF900020) END(0xFF900023)
WIDTH(8) mem_EVT_IVG10 TYPE(RAM)
START(0xFF900024) END(0xFF900027) WIDTH(8)
mem_EVT_IVG11 TYPE(RAM) START(0xFF900028)
END(0xFF90002B) WIDTH(8) mem_EVT_IVG12
TYPE(RAM) START(0xFF90002C) END(0xFF90002F)
WIDTH(8) mem_EVT_IVG13 TYPE(RAM)
START(0xFF900030) END(0xFF900033) WIDTH(8)
mem_EVT_IVG14 TYPE(RAM) START(0xFF900034)
END(0xFF900037) WIDTH(8) mem_EVT_IVG15
TYPE(RAM) START(0xFF900038) END(0xFF90003B)
WIDTH(8) mem_sysstack TYPE(RAM)
START(0xFF90003C) END(0xFF90083B) WIDTH(8)
mem_l1_data_b TYPE(RAM) START(0xFF90083C)
END(0xFF903FFF) WIDTH(8) mem_l1_data_b_cache
TYPE(RAM) START(0xFF904000) END(0xFF907FFF)
WIDTH(8)
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Memory issues on 64 point data batches

• Still did not work
• Did I change the memory map correctly?
• No seems okay as works with 32 but perhaps
  having caching issue
• Went back to old memory map
• Went to configure external SDRAM and use that
• Modified only 1 array left channel
• Left channel fails right channel works
• Spending too much time in context switching
• Group ReadThread and WriteThread code together
• Does not even work with 32 !!!!!!
• Am convinced that there is a logical issue
  associated with the semaphore handling.

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Bonus 20 bonus

• If you can get all parts of Lab. 5 running and
  then solve this issue of why fails at 64 points
  (even when not wasting cycles) 20 bonus on
  this lab. marks and either a mention or a
  co-author-ship on one of the Circuit Cellar
  articles
• May even be worth some money if I manage to sell
  the articles