Segment 14

In this sub-session, the assistant implemented three synthesis optimizations based on previous perf stat analysis: a Vec recycling pool to reduce jemalloc alloc/dealloc overhead, interleaved A+B evaluation for better instruction-level parallelism, and software prefetch in eval loops. Microbenchmarking showed only ~1% improvement, and perf profiling revealed that the recycling pool was ineffective because the majority of allocations came from temporary LinearCombination objects created inside enforce closures via Boolean::lc() and similar methods. The assistant then pivoted to a new approach: adding add_to_lc and sub_from_lc methods to Boolean and add_lc to Num, allowing direct modification of an existing LinearCombination without creating temporary objects. The hottest call sites in UInt32::addmany, SHA-256 gadgets, and lookup closures were patched to use these new methods, and the code was rebuilt for further measurement.

The Optimization That Wasn't: How Profiling Revealed the True Bottleneck in Groth16 Synthesis 3503 words

Chunks

• When Theory Meets Practice: The Disappointing Benchmark That Reshaped a Synthesis Optimization Campaign
  1803 words
• The Pivot: When Profiling Revealed the True Bottleneck in Groth16 Synthesis
  2406 words