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glaucus

xxhash

Build

Section titled “Build”
  • xxhsum was benchmarked using xxhsum --benchmark-all -i10
  • -DLIBXXH_DISPATCH=1 increases size, decreases performance by 2x and requires an explicit include of xxh_x86dispatch.h
  • -DXXH_FORCE_MEMORY_ACCESS=1 forces a gccism that does nothing on modern compilers (openbsd uses it by default)
  • -DXXH_INLINE_ALL=1 breaks the build
  • Default CFLAGS use -O3 which result in the best performance/size ratio with clang (gcc’s -O3 is bloated, use -O2 instead)
  • -Os regresses by at least 2-3x with clang even when -DXXH_NO_INLINE_HINTS=0 -DXXH_SIZE_OPT=0 (gcc’s -Os is closer to -O2)
  • No safe way to pass LDFLAGS
  • Pass PREFIX and DISPATCH=1 (for SSE/AVX on x86-64) to check and install targets as they are not detected in the Makefile

Package

Section titled “Package”
  • xxh3.h is no longer useful and will be removed in 0.9.0

References

Section titled “References”