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@Kamirus Kamirus commented Jun 10, 2025

Do not merge: Just an experiment of using the motoko_debugger in the new-base

Cases I wanted to test:

  • Simple main-program with mops sources
  • Debugging tests

Check out this branch locally and try one of the changed files. Follow the instructions on top of the file as a starting point.

Current limitations that I've found:

  • Most test files e.g. test/List.test.mo do not work and fail with index out of bounds: the len is 27 but the index is 30, seems like bigger wasms are problematic
  • The list command (and transitively other commands e.g. thread step-in with similar output): sometimes produces wrong output. The code line shown might not correspond to the actual one. See the changed files.
  • Use of mops packages break the list output, frequent File not found: "./internals"
  • read local works great for primitives but complex types like objects are just memory addresses.

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github-actions bot commented Jun 10, 2025

✨ Documentation preview for a3ff366:

https://dfinity.github.io/new-motoko-base/pull/327 (source code)

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Benchmark Results

bench/ArrayBuilding.bench.mo $({\color{gray}0\%})$

Large known-size array building

Compares performance of different data structures for building arrays of known size.

Instructions: ${\color{gray}0\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

1000 100000 1000000
List 612_011 $({\color{gray}0\%})$ 53_730_969 $({\color{gray}0\%})$ 531_478_624 $({\color{gray}0\%})$
Buffer 367_424 $({\color{gray}0\%})$ 36_403_920 $({\color{gray}0\%})$ 364_004_168 $({\color{gray}0\%})$
pure/List 318_496 $({\color{gray}0\%})$ 31_604_567 $({\color{gray}0\%})$ 316_062_532 $({\color{gray}0\%})$
VarArray ?T 201_911 $({\color{gray}0\%})$ 19_903_407 $({\color{gray}0\%})$ 199_003_655 $({\color{gray}0\%})$
VarArray T 178_245 $({\color{gray}0\%})$ 17_503_741 $({\color{gray}0\%})$ 175_003_989 $({\color{gray}0\%})$
Array (baseline) 44_088 $({\color{gray}0\%})$ 4_103_584 $({\color{gray}0\%})$ 41_003_832 $({\color{gray}0\%})$

Heap

1000 100000 1000000
List 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
Buffer 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
pure/List 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
VarArray ?T 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
VarArray T 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
Array (baseline) 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$

Garbage Collection

1000 100000 1000000
List 10.05 KiB $({\color{gray}0\%})$ 797.56 KiB $({\color{gray}0\%})$ 7.67 MiB $({\color{gray}0\%})$
Buffer 8.71 KiB $({\color{gray}0\%})$ 782.15 KiB $({\color{gray}0\%})$ 7.63 MiB $({\color{gray}0\%})$
pure/List 19.95 KiB $({\color{gray}0\%})$ 1.91 MiB $({\color{gray}0\%})$ 19.07 MiB $({\color{gray}0\%})$
VarArray ?T 8.24 KiB $({\color{gray}0\%})$ 781.68 KiB $({\color{gray}0\%})$ 7.63 MiB $({\color{gray}0\%})$
VarArray T 8.23 KiB $({\color{gray}0\%})$ 781.67 KiB $({\color{gray}0\%})$ 7.63 MiB $({\color{gray}0\%})$
Array (baseline) 4.3 KiB $({\color{gray}0\%})$ 391.02 KiB $({\color{gray}0\%})$ 3.82 MiB $({\color{gray}0\%})$
bench/FromIters.bench.mo $({\color{gray}0\%})$

Benchmarking the fromIter functions

Columns describe the number of elements in the input iter.

Instructions: ${\color{gray}0\%}$
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Instructions

100 10_000 100_000
Array.fromIter 53_373 $({\color{gray}0\%})$ 5_152_334 $({\color{gray}0\%})$ 51_503_949 $({\color{gray}0\%})$
List.fromIter 35_436 $({\color{gray}0\%})$ 3_421_823 $({\color{gray}0\%})$ 34_204_824 $({\color{gray}0\%})$
List.fromIter . Iter.reverse 56_149 $({\color{gray}0\%})$ 5_392_962 $({\color{gray}0\%})$ 53_907_349 $({\color{gray}0\%})$

Heap

100 10_000 100_000
Array.fromIter 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
List.fromIter 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
List.fromIter . Iter.reverse 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$

Garbage Collection

100 10_000 100_000
Array.fromIter 2.76 KiB $({\color{gray}0\%})$ 234.79 KiB $({\color{gray}0\%})$ 2.29 MiB $({\color{gray}0\%})$
List.fromIter 3.51 KiB $({\color{gray}0\%})$ 312.88 KiB $({\color{gray}0\%})$ 3.05 MiB $({\color{gray}0\%})$
List.fromIter . Iter.reverse 5.11 KiB $({\color{gray}0\%})$ 469.17 KiB $({\color{gray}0\%})$ 4.58 MiB $({\color{gray}0\%})$
bench/ListBufferNewArray.bench.mo $({\color{gray}0\%})$

List vs. Buffer for creating known-size arrays

Performance comparison between List and Buffer for creating a new array.

Instructions: ${\color{gray}0\%}$
Heap: ${\color{gray}0\%}$
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Instructions

0 (baseline) 1 5 10 100 (for loop)
List 1_753 $({\color{gray}0\%})$ 3_319 $({\color{gray}0\%})$ 10_314 $({\color{gray}0\%})$ 15_845 $({\color{gray}0\%})$ 82_859 $({\color{gray}0\%})$
pure/List 1_450 $({\color{gray}0\%})$ 1_564 $({\color{gray}0\%})$ 2_738 $({\color{gray}0\%})$ 4_205 $({\color{gray}0\%})$ 33_746 $({\color{gray}0\%})$
Buffer 2_378 $({\color{gray}0\%})$ 2_539 $({\color{gray}0\%})$ 3_905 $({\color{gray}0\%})$ 5_612 $({\color{gray}0\%})$ 39_474 $({\color{gray}0\%})$

Heap

0 (baseline) 1 5 10 100 (for loop)
List 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
pure/List 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$
Buffer 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$ 272 B $({\color{gray}0\%})$

Garbage Collection

0 (baseline) 1 5 10 100 (for loop)
List 576 B $({\color{gray}0\%})$ 616 B $({\color{gray}0\%})$ 776 B $({\color{gray}0\%})$ 884 B $({\color{gray}0\%})$ 1.93 KiB $({\color{gray}0\%})$
pure/List 360 B $({\color{gray}0\%})$ 380 B $({\color{gray}0\%})$ 460 B $({\color{gray}0\%})$ 560 B $({\color{gray}0\%})$ 2.3 KiB $({\color{gray}0\%})$
Buffer 856 B $({\color{gray}0\%})$ 864 B $({\color{gray}0\%})$ 896 B $({\color{gray}0\%})$ 936 B $({\color{gray}0\%})$ 1.62 KiB $({\color{gray}0\%})$
bench/PureListStackSafety.bench.mo $({\color{gray}0\%})$

List Stack safety

Check stack-safety of the following pure/List-related functions.

Instructions: ${\color{gray}0\%}$
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Instructions

pure/List.split 27_403_700 $({\color{gray}0\%})$
pure/List.all 9_301_156 $({\color{gray}0\%})$
pure/List.any 9_401_585 $({\color{gray}0\%})$
pure/List.map 26_005_117 $({\color{gray}0\%})$
pure/List.filter 24_305_592 $({\color{gray}0\%})$
pure/List.filterMap 30_606_216 $({\color{gray}0\%})$
pure/List.partition 24_706_539 $({\color{gray}0\%})$
pure/List.join 38_606_854 $({\color{gray}0\%})$
pure/List.flatten 29_607_262 $({\color{gray}0\%})$
pure/List.take 27_407_282 $({\color{gray}0\%})$
pure/List.drop 11_004_661 $({\color{gray}0\%})$
pure/List.foldRight 21_806_962 $({\color{gray}0\%})$
pure/List.merge 36_411_001 $({\color{gray}0\%})$
pure/List.chunks 61_513_741 $({\color{gray}0\%})$
pure/Queue 161_571_999 $({\color{gray}0\%})$

Heap

pure/List.split 272 B $({\color{gray}0\%})$
pure/List.all 272 B $({\color{gray}0\%})$
pure/List.any 272 B $({\color{gray}0\%})$
pure/List.map 272 B $({\color{gray}0\%})$
pure/List.filter 272 B $({\color{gray}0\%})$
pure/List.filterMap 272 B $({\color{gray}0\%})$
pure/List.partition 272 B $({\color{gray}0\%})$
pure/List.join 272 B $({\color{gray}0\%})$
pure/List.flatten 272 B $({\color{gray}0\%})$
pure/List.take 272 B $({\color{gray}0\%})$
pure/List.drop 272 B $({\color{gray}0\%})$
pure/List.foldRight 272 B $({\color{gray}0\%})$
pure/List.merge 272 B $({\color{gray}0\%})$
pure/List.chunks 272 B $({\color{gray}0\%})$
pure/Queue 272 B $({\color{gray}0\%})$

Garbage Collection

pure/List.split 3.05 MiB $({\color{gray}0\%})$
pure/List.all 328 B $({\color{gray}0\%})$
pure/List.any 328 B $({\color{gray}0\%})$
pure/List.map 3.05 MiB $({\color{gray}0\%})$
pure/List.filter 3.05 MiB $({\color{gray}0\%})$
pure/List.filterMap 3.05 MiB $({\color{gray}0\%})$
pure/List.partition 3.05 MiB $({\color{gray}0\%})$
pure/List.join 3.05 MiB $({\color{gray}0\%})$
pure/List.flatten 3.05 MiB $({\color{gray}0\%})$
pure/List.take 3.05 MiB $({\color{gray}0\%})$
pure/List.drop 328 B $({\color{gray}0\%})$
pure/List.foldRight 1.53 MiB $({\color{gray}0\%})$
pure/List.merge 4.58 MiB $({\color{gray}0\%})$
pure/List.chunks 7.63 MiB $({\color{gray}0\%})$
pure/Queue 18.31 MiB $({\color{gray}0\%})$
bench/Queues.bench.mo $({\color{gray}0\%})$

Different queue implementations

Compare the performance of the following queue implementations:

  • pure/Queue: The default immutable double-ended queue implementation.
    • Pros: Good amortized performance, meaning that the average cost of operations is low O(1).
    • Cons: In worst case, an operation can take O(size) time rebuilding the queue as demonstrated in the Pop front 2 elements scenario.
  • pure/RealTimeQueue
    • Pros: Every operation is guaranteed to take at most O(1) time and space.
    • Cons: Poor amortized performance: Instruction cost is on average 3x for pop and 8x for push compared to pure/Queue.
  • mutable Queue
    • Pros: Also O(1) guarantees with a lower constant factor than pure/RealTimeQueue. Amortized performance is comparable to pure/Queue.
    • Cons: It is mutable and cannot be used in shared types (not shareable).

Instructions: ${\color{gray}0\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

pure/Queue pure/RealTimeQueue mutable Queue
Initialize with 2 elements 3_571 $({\color{gray}0\%})$ 2_592 $({\color{gray}0\%})$ 3_401 $({\color{gray}0\%})$
Push 500 elements 103_492 $({\color{gray}0\%})$ 867_120 $({\color{gray}0\%})$ 243_585 $({\color{gray}0\%})$
Pop front 2 elements 98_792 $({\color{gray}0\%})$ 5_009 $({\color{gray}0\%})$ 4_326 $({\color{gray}0\%})$
Pop 150 front&back 106_545 $({\color{gray}0\%})$ 350_417 $({\color{gray}0\%})$ 140_211 $({\color{gray}0\%})$

Heap

pure/Queue pure/RealTimeQueue mutable Queue
Initialize with 2 elements 324 B $({\color{gray}0\%})$ 300 B $({\color{gray}0\%})$ 352 B $({\color{gray}0\%})$
Push 500 elements 8.08 KiB $({\color{gray}0\%})$ 8.17 KiB $({\color{gray}0\%})$ 19.8 KiB $({\color{gray}0\%})$
Pop front 2 elements 240 B $({\color{gray}0\%})$ 240 B $({\color{gray}0\%})$ 192 B $({\color{gray}0\%})$
Pop 150 front&back -4.42 KiB $({\color{gray}0\%})$ -492 B $({\color{gray}0\%})$ -11.45 KiB $({\color{gray}0\%})$

Garbage Collection

pure/Queue pure/RealTimeQueue mutable Queue
Initialize with 2 elements 508 B $({\color{gray}0\%})$ 444 B $({\color{gray}0\%})$ 456 B $({\color{gray}0\%})$
Push 500 elements 10.1 KiB $({\color{gray}0\%})$ 137.84 KiB $({\color{gray}0\%})$ 344 B $({\color{gray}0\%})$
Pop front 2 elements 12.19 KiB $({\color{gray}0\%})$ 528 B $({\color{gray}0\%})$ 424 B $({\color{gray}0\%})$
Pop 150 front&back 15.61 KiB $({\color{gray}0\%})$ 49.66 KiB $({\color{gray}0\%})$ 12.1 KiB $({\color{gray}0\%})$

Note: Renamed benchmarks cannot be compared. Refer to the current baseline for manual comparison.

@rvanasa
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rvanasa commented Jun 10, 2025

Good idea to try this!

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