perf: lazy sibling loading in BTreeMap::remove by maksymar · Pull Request #430 · dfinity/stable-structures

maksymar · 2026-04-03T08:08:24Z

This PR implements lazy sibling loading in BTreeMap::remove to avoid redundant node reads.

In remove Case 3 (child at minimum), both left and right siblings were always loaded from stable memory even though only one may be needed. This change loads the left sibling first and skips loading the right sibling entirely when the left can donate an entry. Saves one node load in ~50% of rebalancing cases.

github-actions · 2026-04-03T08:27:34Z

`canbench` 🏋 (dir: ./benchmarks/btreeset) `8de9da0` 2026-04-03 08:24:19 UTC

✅ ./benchmarks/btreeset/canbench_results.yml is up to date
📦 canbench_results_btreeset.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 100 | regressed 0 | improved 0 | new 0 | unchanged 100]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min -104.55K]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min -0.02%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 100 | regressed 0 | improved 0 | new 0 | unchanged 100]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 100 | regressed 0 | improved 0 | new 0 | unchanged 100]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------
CSV results saved to canbench_results.csv

github-actions · 2026-04-03T08:27:34Z

`canbench` 🏋 (dir: ./benchmarks/memory_manager) `8de9da0` 2026-04-03 08:23:56 UTC

✅ ./benchmarks/memory_manager/canbench_results.yml is up to date
📦 canbench_results_memory-manager.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 3 | regressed 0 | improved 0 | new 0 | unchanged 3]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 3 | regressed 0 | improved 0 | new 0 | unchanged 3]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 3 | regressed 0 | improved 0 | new 0 | unchanged 3]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------
CSV results saved to canbench_results.csv

github-actions · 2026-04-03T08:27:35Z

`canbench` 🏋 (dir: ./benchmarks/btreemap) `8de9da0` 2026-04-03 08:25:32 UTC

✅ ./benchmarks/btreemap/canbench_results.yml is up to date
📦 canbench_results_btreemap.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   Improvements detected 🟢
    counts:   [total 252 | regressed 0 | improved 14 | new 0 | unchanged 238]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min -153.26M]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min -2.43%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 252 | regressed 0 | improved 0 | new 0 | unchanged 252]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 252 | regressed 0 | improved 0 | new 0 | unchanged 252]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------

Only significant changes:
| status | name                                    | calls |     ins |  ins Δ% | HI |  HI Δ% | SMI |  SMI Δ% |
|--------|-----------------------------------------|-------|---------|---------|----|--------|-----|---------|
|   -    | btreemap_v2_mem_manager_remove_u64_u64  |       | 721.09M |  -2.01% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_u64_vec8             |       | 561.22M |  -2.02% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_u64_blob8            |       | 555.94M |  -2.05% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_blob8_u64            |       | 573.17M |  -2.09% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_principal            |       | 668.11M |  -2.10% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_blob_8_128           |       | 586.96M |  -2.14% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_vec_4_128            |       | 646.55M |  -2.15% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_vec_8_128            |       | 801.76M |  -2.20% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_blob_32_0            |       | 640.15M |  -2.20% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_blob_16_128          |       | 650.35M |  -2.21% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_100k_u64_u64         |       |   6.78B |  -2.21% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_100k_u64_u64_nocache |       |   6.77B |  -2.21% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_vec_16_128           |       | 897.24M |  -2.23% |  0 |  0.00% |   0 |   0.00% |
|   -    | btreemap_v2_remove_vec8_u64             |       | 736.20M |  -2.43% |  0 |  0.00% |   0 |   0.00% |

ins = instructions, HI = heap_increase, SMI = stable_memory_increase, Δ% = percent change

---------------------------------------------------
CSV results saved to canbench_results.csv

github-actions · 2026-04-03T08:27:35Z

`canbench` 🏋 (dir: ./benchmarks/io_chunks) `8de9da0` 2026-04-03 08:24:49 UTC

✅ ./benchmarks/io_chunks/canbench_results.yml is up to date
📦 canbench_results_io_chunks.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 18 | regressed 0 | improved 0 | new 0 | unchanged 18]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 18 | regressed 0 | improved 0 | new 0 | unchanged 18]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 18 | regressed 0 | improved 0 | new 0 | unchanged 18]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------
CSV results saved to canbench_results.csv

github-actions · 2026-04-03T08:27:36Z

`canbench` 🏋 (dir: ./benchmarks/nns) `8de9da0` 2026-04-03 08:24:14 UTC

✅ ./benchmarks/nns/canbench_results.yml is up to date
📦 canbench_results_nns.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------
CSV results saved to canbench_results.csv

github-actions · 2026-04-03T08:27:37Z

`canbench` 🏋 (dir: ./benchmarks/vec) `8de9da0` 2026-04-03 08:23:55 UTC

✅ ./benchmarks/vec/canbench_results.yml is up to date
📦 canbench_results_vec.csv available in artifacts

---------------------------------------------------

Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 16 | regressed 0 | improved 0 | new 0 | unchanged 16]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

---------------------------------------------------
CSV results saved to canbench_results.csv

perf: lazy simbling loading in remove for BTreeMap

ce3d564

maksymar changed the title ~~perf: lazy simbling loading in remove for BTreeMap~~ perf: lazy simbling loading in BTreeMap::remove Apr 3, 2026

clippy

6bb1144

maksymar changed the title ~~perf: lazy simbling loading in BTreeMap::remove~~ perf: lazy sibling loading in BTreeMap::remove Apr 3, 2026

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perf: lazy sibling loading in BTreeMap::remove#430

perf: lazy sibling loading in BTreeMap::remove#430
maksymar wants to merge 2 commits intomainfrom
maksym/lazy-sibling

maksymar commented Apr 3, 2026 •

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maksymar commented Apr 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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github-actions bot commented Apr 3, 2026

canbench 🏋 (dir: ./benchmarks/btreeset) 8de9da0 2026-04-03 08:24:19 UTC

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canbench 🏋 (dir: ./benchmarks/memory_manager) 8de9da0 2026-04-03 08:23:56 UTC

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canbench 🏋 (dir: ./benchmarks/btreemap) 8de9da0 2026-04-03 08:25:32 UTC

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github-actions bot commented Apr 3, 2026

canbench 🏋 (dir: ./benchmarks/io_chunks) 8de9da0 2026-04-03 08:24:49 UTC

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github-actions bot commented Apr 3, 2026

canbench 🏋 (dir: ./benchmarks/nns) 8de9da0 2026-04-03 08:24:14 UTC

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canbench 🏋 (dir: ./benchmarks/vec) 8de9da0 2026-04-03 08:23:55 UTC

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maksymar commented Apr 3, 2026 •

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`canbench` 🏋 (dir: ./benchmarks/btreeset) `8de9da0` 2026-04-03 08:24:19 UTC

`canbench` 🏋 (dir: ./benchmarks/memory_manager) `8de9da0` 2026-04-03 08:23:56 UTC

`canbench` 🏋 (dir: ./benchmarks/btreemap) `8de9da0` 2026-04-03 08:25:32 UTC

`canbench` 🏋 (dir: ./benchmarks/io_chunks) `8de9da0` 2026-04-03 08:24:49 UTC

`canbench` 🏋 (dir: ./benchmarks/nns) `8de9da0` 2026-04-03 08:24:14 UTC

`canbench` 🏋 (dir: ./benchmarks/vec) `8de9da0` 2026-04-03 08:23:55 UTC