Redis Core Performance Improvements

Redis 8.8 introduces significant performance enhancements across core data types and operations. Key improvements include up to 68% faster MGET with pipelining and I/O threads, up to 25% faster HGETALL on large hashes, up to 40% faster SCAN family operations, and up to 83% faster XREADGROUP for streams. Sorted set operations see up to 74% improvement due to faster float parsing, and bitmap operations are vectorized with AVX-512 for up to 28% gains on modern x86. Persistence and replication also benefit from faster full sync (up to 60%) and reduced BGSAVE overhead. These improvements are achieved through techniques like memory prefetching, batched dict bucket prefetching, stack-allocated vector containers for replies, specialized radix tree optimizations for streams, and AVX-512 vectorization for bitmap operations. Diskless full sync is significantly faster, and fork child overhead during snapshotting is reduced. Replication feed path is also optimized, and primary/replica clients are now serviced within I/O threads.