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Cap LT/LOAD/BRANCH/MEMW_R max_rows at 2^20 #499

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Merged
MauroToscano merged 3 commits into from
Apr 15, 2026
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Cap LT/LOAD/BRANCH/MEMW_R max_rows at 2^20 #499

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d36b05b
perf(tables): cap LT/LOAD/BRANCH/MEMW_R max_rows at 2^20
diegokingston Apr 9, 2026
3a9f94b
Drop incorrect overflow claim from max_rows doc
gabrielbosio Apr 15, 2026
8aecb35
Drop (capped) annotations from max_rows doc
gabrielbosio Apr 15, 2026
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35 changes: 19 additions & 16 deletions prover/src/tables/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -49,29 +49,32 @@ pub use types::BusId;
/// (* MEMW_A formula gives 2^20, but set to 2^19 to match MEMW chunk geometry;
/// benchmarks show better parallel throughput with smaller chunks.)
///
/// | Table | Main | Bus | Eff.width | Max rows |
/// |---------|------|-----|-----------|----------|
/// | MEMW | 49 | 26 | 127 | 2^19 |
/// | MEMW_A | 29 | 20 | 89 | 2^19 * |
/// | CPU | 74 | 40 | 194 | 2^19 |
/// | DVRM | 34 | 34 | 136 | 2^19 |
/// | MUL | 26 | 16 | 74 | 2^20 |
/// | LT | 15 | 9 | 42 | 2^21 |
/// | SHIFT | 27 | 15 | 72 | 2^20 |
/// | LOAD | 18 | 5 | 33 | 2^21 |
/// | BRANCH | 14 | 6 | 32 | 2^21 |
/// | MEMW_R | 10 | 7 | 31 | 2^21 |
/// Capped tables use 2^20, not the 2^21 the formula gives. A 2^21 chunk
/// runs on a single thread and peaks at twice the memory of a 2^20 chunk.
///
/// | Table | Main | Bus | Eff.width | Max rows |
/// |---------|------|-----|-----------|-----------------|
/// | MEMW | 49 | 26 | 127 | 2^19 |
/// | MEMW_A | 29 | 20 | 89 | 2^19 * |
/// | CPU | 74 | 40 | 194 | 2^19 |
/// | DVRM | 34 | 34 | 136 | 2^19 |
/// | MUL | 26 | 16 | 74 | 2^20 |
/// | LT | 15 | 9 | 42 | 2^20 (capped) |
/// | SHIFT | 27 | 15 | 72 | 2^20 |
/// | LOAD | 18 | 5 | 33 | 2^20 (capped) |
/// | BRANCH | 14 | 6 | 32 | 2^20 (capped) |
/// | MEMW_R | 10 | 7 | 31 | 2^20 (capped) |
pub mod max_rows {
pub const CPU: usize = 1 << 19; // 524,288 — eff. width 194
pub const MEMW: usize = 1 << 19; // 524,288 — eff. width 127 (baseline)
pub const MEMW_A: usize = 1 << 19; // 524,288 — eff. width 89
pub const DVRM: usize = 1 << 19; // 524,288 — eff. width 136
pub const MUL: usize = 1 << 20; // 1,048,576 — eff. width 74
pub const LT: usize = 1 << 21; // 2,097,152 — eff. width 42
pub const LT: usize = 1 << 20; // 1,048,576 — eff. width 42 (capped at 2^20)
pub const SHIFT: usize = 1 << 20; // 1,048,576 — eff. width 72
pub const LOAD: usize = 1 << 21; // 2,097,152 — eff. width 33
pub const BRANCH: usize = 1 << 21; // 2,097,152 — eff. width 32
pub const MEMW_R: usize = 1 << 21; // 2,097,152 — eff. width 31
pub const LOAD: usize = 1 << 20; // 1,048,576 — eff. width 33 (capped at 2^20)
pub const BRANCH: usize = 1 << 20; // 1,048,576 — eff. width 32 (capped at 2^20)
pub const MEMW_R: usize = 1 << 20; // 1,048,576 — eff. width 31 (capped at 2^20)
}

/// Per-table maximum row limits, configurable for different environments.
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