25 lines
1.1 KiB
Markdown
25 lines
1.1 KiB
Markdown
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## Estimating fillrate
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Here are some results of simple tests on filling DMA buffer with data.
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Filling DMA buffer requres lot's of memory operations on a bit level rather than doing simple byte/word wide store and copy. And it looks like it's quite a task both for esp32 core and compiler.
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I've done this while optimizing loops and bit logic along with testing compiler results.
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So the testbed is:
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- Matrix modules: 4 x FM6126A based 64x64 modules chained in 256x64
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A simple sketch:
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- allocating single DMA buffs for 256x64
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- allocating (NUM_LEDS*3) bytes for CRGB buffer
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- measuring microseconds for the following calls:
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- clearScreen() - full blanking
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- fillScreenRGB888() with monochrome/gray colors
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- filling some gradient into CRGB buff
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- painting CRGB buff into DMA buff with looped drawPixelRGB888()
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|Pattern |Reference|Ref+SPEED|Optimized|Optimized+SPEED|
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|--|--|--|--|--|
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|fillScreenRGB888()|14570|14570|13400 (8.5% faster)|5520 (164% faster)|
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|CRGB buff fill|760|760|760|760|
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|updateMatrixDMABuffer(CRGB)|7700|32080|55780 (38% faster)|33500(+4.2% slower)|
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to be continued...
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