Implementation:ClickHouse ClickHouse SSE Memcpy

Knowledge Sources	ClickHouse
Domains	Memory, SIMD
Last Updated	2026-02-08 00:00 GMT

Overview

Custom optimized memcpy implementation using SSE2 instructions.

Description

Hand-optimized memcpy using SSE2 loads/stores, aligned stores, and loop unrolling. Avoids glibc symbol dependencies and PLT overhead.

Usage

Use for high-performance memory copying, avoiding glibc dependencies, or when standard memcpy is a bottleneck.

Code Reference

Source Location

• Repository: ClickHouse
• File: base/glibc-compatibility/memcpy/memcpy.h
• Lines: 1-223

Signature

static inline void * inline_memcpy(
    void * __restrict dst_,
    const void * __restrict src_,
    size_t size);

Import

#include <base/glibc-compatibility/memcpy/memcpy.h>

Usage Examples

#include <base/glibc-compatibility/memcpy/memcpy.h>

char src[1024];
char dst[1024];

// Fast optimized copy
inline_memcpy(dst, src, 1024);

// Works for any size
inline_memcpy(dst, src, 7);    // Small size
inline_memcpy(dst, src, 1000); // Medium size  
inline_memcpy(dst, src, 10000); // Large size

Related Pages

• Principle:ClickHouse_ClickHouse_Optimized_Memcpy