timeperfcounter

Timeperfcounter, typically referring to Python’s time.perf_counter function, provides a high-resolution timer for measuring elapsed durations. It returns the value of the system’s most precise clock available for timing short intervals, as a floating-point number representing seconds. The function is designed to be monotonic, meaning its value only increases, and it includes time elapsed during sleep.

Platform and mechanism: time.perf_counter is implemented differently across platforms but aims to offer the best available resolution. On Windows, it may use a high-resolution performance counter; on Unix-like systems, it relies on a monotonic clock such as CLOCK_MONOTONIC. The exact origin of the clock is abstracted away from the user, ensuring a consistent interface for elapsed-time measurements.

Usage: The typical pattern is to capture a start time with time.perf_counter(), execute the code block to be timed, then compute elapsed as time.perf_counter() - start. This makes it suitable for benchmarking, profiling, or timing operations where wall-clock time or system clock changes should not affect results. For higher precision, newer Python versions offer time.perf_counter_ns, which returns integer nanoseconds.

Limitations: The value is a relative timestamp with no fixed relation to real-world dates. It should be used for differences within the same process and session; it is not appropriate for timestamping events across systems. While highly accurate, the exact resolution can vary by platform, and minor overhead from the function call exists.

See also: time.monotonic, time.process_time, and language-specific high-resolution timers in other environments. Time.perf_counter is one of several tools in Python designed to measure performance with minimal interference from system clock adjustments.