Do you have experience in improving system or code performance?

Yes, improving code performance is a common task. For example, in Python, you can optimize algorithms, use built-in functions and data structures, and profile your code with the cProfile module to identify bottlenecks.

An example of optimizing the counting of unique elements:

# Slow method
unique = []
for item in data:
    if item not in unique:
        unique.append(item)

# Fast method
unique = list(set(data))

You can also use multithreading or asynchronous programming to speed up input/output, and for computationally intensive tasks, libraries implemented in C, such as NumPy.