FrontierRefactor Introduces First Code Performance Benchmark: 41% of Agent Patches Pass Tests with Zero Gain or Regressions
Published in arXiv:2610.25834, FrontierRefactor establishes the industry's first evaluation benchmark targeting autonomous coding agents on multi-scale, performance-oriented codebase refactoring. Unlike traditional benchmarks like SWE-bench that measure only functional pass rates, FrontierRefactor spans seven programming languages and 60 Amdahl-qualified tasks ranging from kernels to full repositories (10^1 to 10^4+ LOC). Initial evaluations reveal that over 41% of agent patches pass functional equivalence suites yet yield zero verified speedup—with 19.3% triggering severe runtime performance regressions, highlighting the vital need for multi-turn profiling feedback.

Key Takeaways
- FrontierRefactor (arXiv:2610.25834) introduces the first multi-scale performance-oriented codebase refactoring benchmark across 7 languages and 60 tasks
- Reveals acute blindspot: over 41% of agent submissions pass functional tests but deliver zero verified acceleration (19.3% regress, 21.9% noise)
- Cross-language rewrites offer high theoretical speedups but suffer contract collapse; in-place optimizations preserve contracts but fail without profiling
- Multi-turn execution-timing feedback serves as the decisive lever, multiplying strict success rates across complex codebases