<antirez>

2 days ago

Raspberry Pi is a popular platform for embedded and IoT programming, and Redis is well-suited for data storage on it due to its small memory footprint and append-only write pattern.
Adapting Redis to ARM processors required handling unaligned memory accesses: ARM v6 handles word-sized accesses but not multi-word or floating-point instructions, and the Linux kernel's fix-up is slow and incomplete.
Redis now defines USE_ALIGNED_ACCESS for architectures lacking unaligned support, using memcpy for safe access and fixing crashes on ARM and SPARC.
The hash function was updated to SipHash for security and alignment safety, replacing Murmurhash2.
Performance on Pi 3 reaches ~28,000 ops/sec (non-pipelined) and ~80,000 ops/sec with pipelining; on older Model B, it's ~2,000 ops/sec.
Future plans include integrating stream data type in Redis 4.2 for IoT data bus and making Pi a primary target platform for Redis.
The author invites community feedback on embedded applications and improvements.

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