SIMD Backends

svb provides SIMD-accelerated encode and decode for all codec variants. The scalar path is always compiled and serves as the correctness reference.

Available backends

simd-auto

simd-auto detects the best available path at runtime using is_x86_feature_detected! on x86-64 and unconditional NEON on AArch64. This is the recommended flag for most users.

On x86-64, simd-auto selects AVX2 if available, then SSSE3, then scalar. On AArch64, NEON is always selected (NEON is mandatory on AArch64).

simd-auto requires std for runtime CPU detection. In no_std contexts, use a compile-time flag instead.

Compile-time flags

simd-avx2, simd-ssse3, and simd-neon compile in the SIMD path and assume it is available at runtime. These are appropriate when the target CPU is known:

# Cross-compile to a known AVX2 target
svb = { version = "0.2", features = ["simd-avx2"] }

or with RUSTFLAGS="-C target-cpu=native" where the build host and run host are the same.

Pipeline coverage

SIMD paths are provided for individual codec variants and for both high-level pipelines:

• VBZ pipeline (encode_vbz / decode_vbz_fused): fused SVB16 + zigzag + delta in a single SIMD loop on x86-64 (SSSE3/AVX2) and AArch64 (NEON).
• SVB-ZD pipeline (encode_svbzd / decode_svbzd_fused): fused U32Classic + unzigzag + undelta. Encode computes zigzag-delta inline via SIMD (eliminates the intermediate Vec<u32> allocation), decode collapses all three stages into one SIMD loop.

Decode throughput

With simd-auto on a modern x86-64 machine, decode throughput for all codec variants is in the range of 1.3–4 GB/s depending on variant and input size. See Performance for detailed numbers.