{ "baseline": "long-20261109", "date": "2026-11-09", "baseline_commit": "5ecb52fe03558e6165d97c3d76be6ade0f42d150", "source_state": "Working tree on top of baseline_commit (uncommitted): the v0.2.12 CHANGELOG.md entries. sha256 identifies the measured sources.", "c_library": "zstd 1.5.7 (zstd-ffi vendored submodule f8745da6ff1ad1e7bab384bd1f9d742439278e99), cc -O3, ZSTD_DISABLE_ASM, ZSTD_LEGACY_SUPPORT=0, single-threaded", "rustc": "rustc 1.99.1 (58cf8f9c3 2026-10-13)\nbinary: rustc\ncommit-hash: 58cf8f9c35b355199727627d07ae34a4e2846d67\ncommit-date: 2026-10-13\nhost: x86_64-unknown-linux-gnu\nrelease: 1.99.1\nLLVM version: 23.1.1", "c_compiler": "cc (Ubuntu 15.2.0-16ubuntu1) 15.2.0", "kernel": "Linux 7.0.0-42-generic #42-Ubuntu SMP PREEMPT_DYNAMIC Thu Oct 15 08:06:44 UTC 2026 x86_64", "target": "x86_64-unknown-linux-gnu", "cpu": "AMD Ryzen 9 7950X", "affinity": "Linux KVM guest with two vCPUs: the encoder suite, then the decoder suite, each in one Criterion process pinned to vCPU 1; nothing else ran in the guest. Other tenants loaded the host: a fixed C decode varied by 8-43% (p10-p90 wall time) through the day, so sampling was lengthened to average over the noise.", "rustflags": "unset; Cargo release defaults (bench profile), runtime SIMD dispatch (AVX-512 level on this host; the decoder runs its block loops at the AVX2 level)", "api_mode": "cold one-shot APIs: construction, allocation, the call and disposal", "levels": "-5, -1, 1-22", "versions": { "c-zstd": "1.5.7", "mzstd": "0.2.12" }, "sampling": { "samples": 50, "warmup_seconds": 3, "requested_measurement_seconds": 6, "bootstrap_resamples": 100000, "confidence_level": 0.95, "note": "Criterion defaults otherwise; Criterion extends slow cases to collect all samples." }, "plotting": "Matplotlib 3.10.8", "size_manifest": "encoder-comparison-2026-11-09/sizes.csv", "criterion_samples": "encoder-comparison-2026-11-09/criterion-samples.json.gz", "reproduction_command": "cd benchmarks/comparison && taskset -c 1 target/release/deps/encoders- 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The guest shares its host's caches with other tenants.", "C then mzstd run consecutively per case in a fixed order inside one Criterion process. Individual mean confidence intervals do not account for all host variation or multiple comparisons.", "Every corpus/level pair has equal weight, including empty and tiny input; the median describes this corpus, not a production workload.", "Cold APIs include allocation and the allocator state the process has reached, including glibc's dynamic mmap and trim thresholds.", "The C library is built by zstd-ffi with cc defaults and without its Huffman assembly decoder." ], "started_at_utc": "2026-11-09T15:08:37Z", "finished_at_utc": "2026-11-09T16:18:29Z", "artifact_sha256": { "encoder-comparison.csv": "87b82f82970057e24250ccec2bca44154128690f618e0fb0090e6e1a08243535", "encoder-comparison-2026-11-09/sizes.csv": "e0498876dc163069bf306442d99b9f277a339e69305dbc42fa571a598d0dd525", "encoder-comparison-2026-11-09/criterion-samples.json.gz": "baf628ae1e316c18d83cdac3368c937eeb1820d5d12194abe0a048393c5fcd1a" } }