Go: Runtime Map Performance Optimization
ArsenySamoylov committed a significant rewrite of the runtime's map hashing functions, replacing assembly implementations with SIMD intrinsics to improve performance by up to 8% in map operations.
Duration: PT1M50S
Episode overview
This episode is a short developer briefing from Go.
It explains recent repository work in plain language.
- Show: Go
- Published: 2026-05-11T10:01:01Z
- Audio duration: PT1M50S
Transcript excerpt
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Good morning, this is your Go development briefing for May 11th, 2026.
Today we have one notable commit to the Go runtime. ArsenySamoylov has rewritten the internal runtime maps MemHash32 and MemHash64 functions using SIMD and archsimd intrinsics, replacing the previous assembly implementations.
This change introduces a new GOEXPERIMENT=simd flag that enables SIMD-optimized hash functions for map operations. The benchmark results show promising performance improvements - up to 8% faster for map access operations with int64 keys, and consistent gains across map assignment and lookup operations. The geometric…
The commit affects multiple architecture files including AMD64, ARM64, and 386 assembly code, consolidating the hash implementations into a more maintainable structure. Some benchmarks show temporary regressions due to basic block alignment changes, but the overall trend favors the new implementation.
This work adds several new files including memhash_aes_simd.go and memhash_aes_asm.go, creating a cleaner separation between SIMD and non-SIMD code paths. The change also updates the build dependency graph to accommodate the new internal structure.
Looking ahead: developers will be…
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