| # Final release measurements |
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| These source-bound results compare the complete V5, V7 and final V8 engines on Python 3.12.14 / Linux / overlay. Each trial includes admission, automatic maintenance, persistence and an explicit final checkpoint drain. Setup/open and final value/receipt validation are excluded. All 63 trials passed unchanged-source guards and exact contents/receipt validation. These are POSIX regular-file prototype measurements, not native NTFS results. |
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| ## Single-key workloads |
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| Each trial has 128 durable single-key transactions with 128-byte values and a 32,768-block arena. There are three trials per workload with rotated backend order. The table shows medians and ratios of medians. |
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| | Initial files | Workload | V5 tx/s | V7 tx/s | V8 tx/s | V8/V7 | V8/V5 | |
| |---|---|---|---|---|---|---| |
| | 4,096 | Hot prefix | 2006.66 | 1600.22 | 1908.01 | 1.192x | 0.951x | |
| | 4,096 | Uniform | 1782.60 | 1418.28 | 1472.93 | 1.039x | 0.826x | |
| | 16,384 | Hot prefix | 2089.76 | 1413.31 | 1411.53 | 0.999x | 0.675x | |
| | 16,384 | Uniform | 1265.12 | 794.46 | 977.93 | 1.231x | 0.773x | |
| | 65,536 | Hot prefix | 1592.08 | 1138.89 | 1370.66 | 1.204x | 0.861x | |
| | 65,536 | Uniform | 1214.78 | 910.83 | 841.64 | 0.924x | 0.693x | |
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| V8/V7 single-key throughput ranges from 0.924x to 1.231x. The 65,536-file uniform case is 7.6% lower than V7; the 16,384-file hot-prefix case is effectively equal in these three-trial medians. Against V5, V8 ranges from 0.675x to 0.951x, with a worst measured throughput deficit of 32.5%. V5 has the weaker arena-admission contract. These results support neither a universal speedup nor an NTFS-superiority claim. |
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| All three engines request identical host-write bytes and perform 132 fsync calls in each single-key trial. Every V8 single-key trial has 128 fast accepts, zero exact fallbacks, two exact compiler calls and zero full-graph scans. |
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| ## Separate growing-cell stress workload |
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| This workload starts with an empty published namespace and performs 64 atomic transactions, each adding 128 new keys with 128-byte values: 8,192 logical key updates. It deliberately exposes growth of a pending reservation cell anchored to an empty root. Transaction throughput and logical-key throughput differ by 128 and must not be substituted for the single-key rates above. There are three trials per backend, with the same complete final-drain timing boundary. |
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| | Engine | Durable atomic tx/s | Logical key updates/s | Final checkpoint ms | |
| |---|---|---|---| |
| | V5 | 186.96 | 23930.40 | 224.60 | |
| | V7 | 37.66 | 4820.00 | 247.06 | |
| | V8 | 135.38 | 17328.43 | 281.08 | |
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| V8 improves 3.595x over V7 on this specific structural stress and reaches 0.724x V5 throughput. All three engines request identical host-write bytes and perform 66 fsync calls. V8 has 64 fast accepts, zero exact fallbacks, one exact compiler call and no full-graph scan. The gain demonstrates this workload's reduced reservation recounting, not a general filesystem frontier. |
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| ## Interpretation and reproduction |
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| The weighted persistent budget keeps encoded entry weights and leaf sums, copies the affected symbolic path, and caches subtree page counts. This removes repeated serialization and repartitioning of a growing pending cell. The single-key profile already showed much of the remaining time in actual checkpoint construction/validation and fsync, so ordinary-workload gains are more modest and some regressions remain. |
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| Raw trials, latency samples, engine counters, allocation metadata, logical-workload digests and source hashes are in `benchmark_final_results.json`. Counter names are implementation-scoped: for example, `reservation_entry_encodings` counts initial published-leaf weights; a zero value for empty genesis does not mean newly offered keys required no encoding. |
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| Run the frozen experiment from the source root: |
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| ```bash |
| python3 experiments/benchmark_final.py --namespaces 4096 16384 65536 --operations 128 --trials 3 --pool-blocks 32768 |
| ``` |
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| Add `--output rerun_benchmark_results.json` to preserve the supplied result. No simulated flush delay, direct IO, cache dropping, NAND traffic measurement or physical power-cut qualification is used. All live logical data remain in RAM. |
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| Engine and benchmark hashes: |
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| ```json |
| { |
| "benchmark": "6bdd994db6ab30d9a30e1e393534d18528218bfe4c2afc3f4a7fb5840f7b2f74", |
| "v5": "3685cd31ebf282050e26001439f3bd06b9cf3cff765ab7085399786c2f9616bd", |
| "v7": "a67c93290fd561eff480f84b483dee0b44833c694da9b96c5d830af00616b980", |
| "v8": "e22e219b85e4b2a777b295ecad616cf4ef400e0189d7d7583d14f432d89ed807" |
| } |
| ``` |
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|
