123: a 'clamp to zero' written as a BITWISE MASK (x & (x >> 31)) compiles branchlessly while
the same thing as a TERNARY branches -- the opposite of the intuition. Worker B's MIN half now
matches exactly with the bitwise form. The MAX half (branchless slt/negu/and, i.e. x & -(x>0))
remains UNREACHED by any ternary or bitwise spelling, with a plausible SDK min/max macro as the
source. Recorded as a named open question.
124: worker B found that the partition design CONFOUNDED the size/redundancy measurement. The
partitions were rank-interleaved by the original worklist order (tier, size, address), not by
redundancy, so 'my <=200 B hit rate was high because my slice happened to be redundancy-rich,
not because small rows are inherently easy'. The within-worker evidence for 'cost is redundancy'
stands (A: 548 B first-attempt vs 176 B nine failures), but any CROSS-worker band comparison was
measuring the partition, not the rows. Fixed by re-partitioning on global redundancy. General
lesson: when work is divided among workers, any per-worker statistic is contaminated by the
division.
Christopher Williams
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