fmt.Sprintf() is well-known for not being opimal in terms of CPU and memory allocations. If these functions are called in hot paths such as pkg/policy/api or even parts of pkg/policy, it can be quite impactful, especially in environments that experience high or bursty churn.

Writing a benchmark and replacing the current code with strings.Builder or bytes.NewBuffer can show us if we can achieve some quick wins.

Some examples:

• pkg/policy/api: Optimize FQDNSelector String() #19570
• pkg/labels: Optimize SortedList() and FormatForKVStore() #19423