perf: Reduce prove peak memory and switch to jemalloc #277
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@Paradox Can you please rebase it with main, pr makes quite a few changes which breaks compatibility, such as -
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- Destructure WhirR1CSCommitment to drop masked/random polynomials before WHIR prove_batch/prove, saving ~256 MB in dual-witness path - Defer public input weight vector allocation until after alphas are consumed - Drop program and witness_generator before prove call (~60 MB) - Add feature-gated jemalloc as default allocator (RSS: 2.39 GB -> 1.90 GB) - Add release-fast build profile (30s vs 2.5min) Profiling peak: 2.24 GB -> 1.92 GB RSS with jemalloc: 1.90 GB (complete_age_check, 1.1M constraints)
…commits Move drop(self.program) and drop(self.witness_generator) immediately after extracting public input indices, before the NTT-heavy commit phase. Also drop acir_witness_idx_to_value_map right after its last use in each branch rather than after both branches.
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Feb 10, 2026
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| impl R1CSSolver for LazyR1CS { |
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The R1CSSolver for LazyR1CS is same as that of the R1CS implementation. Instead of the common code, consider extracting into common func, using macros etc.
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| fn ensure_decompressed(&self) -> &(Interner, SparseMatrix, SparseMatrix, SparseMatrix) { |
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Consider using Result<&(...)> for better logging
| postcard::to_allocvec(&matrices).expect("Failed to serialize R1CS matrices"); | ||
| let mut compressed = Vec::new(); | ||
| { | ||
| let mut encoder = XzEncoder::new(&mut compressed, 6); |
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In file/bin.rs, the encoding used was xz level 9. it's better to have a global const which is 9 and used here as well
| zeroize = "1.8.1" | ||
| xz2 = "0.1.7" | ||
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| /// After the first access the decompressed matrices live in `cached`, | ||
| /// so the compressed blob is dead weight. Call this after the first | ||
| /// access to reclaim ~10 MB for a typical circuit. | ||
| pub fn free_compressed(&mut self) { |
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Consider adding an assertion in free_compressed() to verify cache is populated: assert!(self.cached.get().is_some(), "Must access matrices before freeing");
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Reduce Peak Memory During Prove Step
Problem
After adding public inputs, the prove step for
complete_age_checkregressed from 1.84 GB to 2.24 GB peak memory.Changes
Memory optimization (2.24 GB → 1.92 GB, −320 MB)
WhirR1CSCommitmentin both single and dual witness paths to take ownership of masked/random polynomials, enabling explicitdrop()before entering WHIR'sprove_batch/proveadd_public_inputs_to_transcript+build_public_weights) to defer the 64 MB allocation until after alphas are consumedprogramandwitness_generatorbefore the prove call since they are only needed during witness generationSwitch default allocator to jemalloc (RSS: 2.39 GB → 1.90 GB, −490 MB)
ProfilingAllocator, enabled by defaultAdd
release-fastbuild profilecargo build --profile release-fastcodegen-units = 16lto = "thin"Benchmark (
complete_age_check, 1.1M constraints)Allocator Comparison
jemalloc was chosen as default for best RSS.
mimalloc was evaluated and rejected (worst RSS despite best wall-clock time).
Root Cause Analysis
The remaining ~80 MB gap from the original 1.84 GB is fully accounted for by the public inputs weight vector:
prove_batch(line 279, read-only external crate)Before public inputs, there were 6 weights; after, 7.
This overhead is inherent to the protocol and cannot be reduced without modifying the WHIR crate or changing the proof transcript structure.