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diff --git a/fillrate.md b/fillrate.md new file mode 100644 index 0000000..b07e1af --- /dev/null +++ b/fillrate.md @@ -0,0 +1,25 @@ +## Estimating fillrate + +Here are some results of simple tests on filling DMA buffer with data. +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. +I've done this while optimizing loops and bit logic along with testing compiler results. + +So the testbed is: + - Matrix modules: 4 x FM6126A based 64x64 modules chained in 256x64 + +A simple sketch: + - allocating single DMA buffs for 256x64 + - allocating (NUM_LEDS*3) bytes for CRGB buffer + - measuring microseconds for the following calls: + - clearScreen() - full blanking + - fillScreenRGB888() with monochrome/gray colors + - filling some gradient into CRGB buff + - painting CRGB buff into DMA buff with looped drawPixelRGB888() + +|Pattern |Reference|Ref+SPEED|Optimized|Optimized+SPEED| +|--|--|--|--|--| +|fillScreenRGB888()|14570|14570|13400 (8.5% faster)|5520 (164% faster)| +|CRGB buff fill|760|760|760|760| +|updateMatrixDMABuffer(CRGB)|7700|32080|55780 (38% faster)|33500(+4.2% slower)| + +to be continued...
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