In software development and high-performance computing (HPC), wall time is the ultimate measure of
Wall time is the "real-world" metric of performance. It tells you how long a process takes in the eyes of a human observer. While CPU time tells you how hard the computer worked, wall time tells you how long you had to wait—making it perhaps the most critical metric for efficiency and productivity in the digital age. wall time
To fully understand wall time, it must be contrasted with other common timing concepts, particularly in computing and performance analysis. To fully understand wall time, it must be
import time start = time.perf_counter() # Monotonic, high-resolution # ... work ... end = time.perf_counter() wall_time = end - start end = time
Here are some practical tips to help you get started with tracking wall time:
While a developer might optimize code to reduce CPU time, the user only cares about wall time—how long they have to wait before they can use the app. If a program has low CPU usage but high wall time, it usually points to a , such as:
This includes CPU time plus all the "waiting" time. The Coffee Shop Analogy: Imagine you go to a coffee shop.