What was the problem with the old maps in Go that led to rewriting them entirely with SwissMap, resulting in a performance increase of about 30%?

The old implementation of maps in Go had several issues:

• It used a hash table with open addressing and linear probing, which led to performance degradation during collisions.
• Inefficient use of cache memory due to the data structure.
• Difficulties with load balancing across buckets.

SwissMap is a new implementation inspired by algorithms from the C++ Abseil library, which uses:

• Open addressing with improved collision management.
• Optimized structures for better CPU cache utilization.
• More efficient memory management and reduced copying.

As a result, it provided approximately a 30% performance increase, improved access time predictability, and reduced memory fragmentation.