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…th widths EXPERIMENTAL successor of mh built on Mul128Fold64 (MUM): unrolled per-length small-key terminal actions (data in both product operands - quadratic products kill pairwise correlations), length folded into the seed, 128-byte 8-chain bulk fetch window with distinct chain secrets, native dual-lane 128-bit form, two-multiply finalizer keeping both widening-product halves. Secrets are sqrt fractions of the first 16 primes. Three measured iterations (v1 175 -> v2 177 -> v3 188/188 both widths, the only clean native 128 measured on our rig); fastest mixed-length latency <= 16B and fastest bulk throughput in the library. Also merges SMHASHER3.md into mbo/hash/README.md (Principles -> Performance -> Quality) with same-run benchmark tables; end-game decisions (mh retirement, defaults, name, streaming) in TODO.md.
- Rename mh2 -> mumbo (MUM + mbo), drop the EXPERIMENTAL label; v4: the length moves from the seed into the finalizer's product operands (streaming-enabling; equally protective) and the 128-bit lane seeds derive from distinct secret pairs so no lane equals the 64-bit hash. - Streaming for mumbo: eager 128-byte block consumption + rolling last-16 window; chunked == one-shot (typed test). - mumbo becomes DefaultHashAlgorithm AND Default128HashAlgorithm. - New //mbo/hash:hash_extra_cc (mbo/hash/hash_extra.h): the NOTICE-bearing transcriptions (rapidhash MIT, xxh64/xxh3 BSD-2) now require explicit linkage; the default hash_cc is notice-free. - Drop mh entirely (never released): hash_mh.h deleted, all references scrubbed from code, tests, README, and CHANGELOG (which now presents mumbo directly). - README: tables updated (mumbo v4 numbers), mumbo design-iteration section replaces the mh failure analysis. v4 SMHasher3 re-verification is running; the doc marks it in flight.
…ble break Every build/test/benchmark job now gates on both lint jobs (benchmark previously gated on nothing, tests only on pre-commit), so a trunk failure stops the matrix early. Also fixes the markdownlint MD056 that trunk caught: the quality table's trailing paragraph had lost its blank line and was absorbed as a table row.
'mumbo jumbo': jumbo::Algorithm (inherits the complete mumbo surface) fronts the native 128-bit form and becomes Default128HashAlgorithm; both structs are complete so either plugs in anywhere. Docs batch: root README hash section (mumbo/jumbo defaults, extras via hash_extra.h, hash_extra_cc target bullet), third-party tables point compliance at hash_extra_cc (hash_cc is notice-free), NOTICE preamble updated accordingly, TODO records the resolved hash_extra decision and the remaining jumbo-streaming idea, hash README tables renamed (jumbo 128 rows) with v4 64-bit re-verification recorded (PASS 188).
… extend perf tables to all algorithms fnv1a (the std::hash family baseline, e.g. MSVC), murmur3, siphash, and the legacy simple join the latency/throughput tables; overview table maps each algorithm to its target (hash.h default vs hash_extra_cc opt-in), NOTICE obligation, seeding, and streaming. Same-rig SMHasher3 batteries for fnv1a/murmur3/siphash are running; their quality rows land when complete.
…88), siphash (PASS) The std::hash baseline quantified: fnv1a passes 7 of 186 tests; murmur3 fails the modern Seed* cluster broadly; siphash is clean as a PRF must be. Overview cells and quality table complete for all algorithms; methodology lists the built-in registrations used.
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…live in the README data sections)
…n the named rule is linked)
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* docs(hash): CI cross-platform performance tables (x86_64 gcc vs arm64 clang) Latency and throughput from PR #235's CI benchmark artifacts (ubuntu-latest / macos-26, mean of 3 repetitions), with the noise and constant-folding caveats stated. The mumbo/rapidhash near-tie and jumbo's 128-bit lead reproduce on both architectures. * docs(hash): drop trailing colons from perf headings (markdownlint MD026)
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The in-house mumbo/jumbo hash family (MUM + mbo; "mumbo jumbo"): built on the widening 64x64->128 multiply, developed in four measured iterations (each: benchmark + full SMHasher3 batteries, documented in
mbo/hash/README.md), and now the library default in all forms.Headlines
mumbo(64) joins rapidhash as the only clean 64-bit passes;jumbo(128) is the only clean 128-bit result we have measured (xxh3-128: 162, murmur3: 123).jumbois the fastest 128-bit hash from 16 bytes up (1.7-2.4x xxh3-128).DefaultHashAlgorithm = mumbo::Algorithm,Default128HashAlgorithm = jumbo::Algorithm. Both structs are complete (each delegates the other width), so either plugs in anywhere.//mbo/hash:hash_extra_cc(hash_extra.h): the NOTICE-bearing transcriptions (rapidhash MIT, xxh64/xxh3 BSD-2) now require explicit linkage - the defaulthash_ccis notice-free. NOTICE/README third-party tables updated accordingly.Design (hash_mumbo.h)
Unrolled per-length small-key terminal actions with the key in BOTH product operands (quadratic products kill pairwise correlations); 17-127B sequential MUM chain with overlapping end loads (no tail loops anywhere); >= 128B eight chains over a 128-byte fetch window with distinct secrets; finalizer keeps both widening-product halves with the length in the product operands; 128-bit form runs two lanes with distinct secret banks and swapped operand roles over a shared 4-chain bulk tier. Secrets: sqrt fractions of the first 16 primes (= SHA-512/SHA-384 IVs).
The data story (mbo/hash/README.md)
hash.hdefault vshash_extra_ccopt-in), NOTICE obligation, seeding, streaming, SMHasher3 verdict.fnv1a, the family behind manystd::hashimplementations (fastest possible 1-byte hash; 10-70x slower than mumbo beyond).Also
trunkandpre-commit.HasStreamingconcept extension).CI benchmark results (run 28753339340; informational - shared runners are noisy)
Values are
ubuntu-latest(x86_64, gcc, 4 vCPU) /macos-26(arm64, Apple clang) mean of 3 repetitions, ns/op.Mixed-length latency (serialized chain):
* gcc constant-folding artifacts on the fixed-size lanes; treat with suspicion.
64-bit one-shot:
128-bit one-shot:
Cross-platform reading: the mumbo/rapidhash near-tie holds on both architectures (rapidhash leads x86_64-gcc bulk, they tie on arm64); jumbo is the fastest 128-bit hash from 256 bytes up on BOTH platforms; the xxh3 mid-size dip and the fnv1a/siphash/simple profiles reproduce everywhere.