Use independent seeds in makeSizedByteStrings#7735
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`makeSizedByteStrings` used the same `H.Seed` for every element, so each generated ByteString was a prefix of the same deterministic byte sequence. Use `unfoldr (Just . Seed.split)` to produce a stream of independent SplitMix seeds instead, giving uncorrelated content across sizes.
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/benchmark nofib |
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zliu41
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Apr 23, 2026
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Use independent seeds
Looks reasonable, but are you sure this is the reason for the "FIXME: this is terrible"? Who added the FIXME?
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Comparing benchmark results of 'nofib' on '0468c1c57d' (base) and '5a6c9917d0' (PR) Results table
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Summary
Fixes the
-- FIXME: this is terribleinplutus-core/cost-model/budgeting-bench/Generators.hs.makeSizedByteStringspassed the sameH.Seedto every call ofmakeSizedByteString, so each generated ByteString was a prefix of the same deterministic byte sequence — smaller ones were literal prefixes of larger ones. This produced correlated inputs for benchmarks that depend on byte content (equality, hashing, string ops).