Performance improvements in the Datadog Agent metrics pipeline | Datadog

This post details performance improvements in the Datadog Agent's metrics pipeline, specifically focusing on optimizing the computation of unique keys for metrics. The team identified a bottleneck in the original algorithm's sorting and deduplication of tags. They implemented several strategies: specializing the sorting algorithm based on the number of tags, switching to a faster hash implementation (murmur3), and optimizing map access with 64-bit keys. The most significant improvement came from redesigning the context generation algorithm to use XOR bitwise operations instead of merging hashes, removing the need for sorting. A custom hash set was introduced for efficient tag deduplication, avoiding the overhead of Go maps.