Measure execution time
123456789101112 | #include <chrono>
int main()
{
using clock = std::chrono::steady_clock;
clock::time_point start = clock::now();
// A long task...
clock::time_point end = clock::now();
clock::duration execution_time = end - start;
} |
This pattern is licensed under the CC0 Public Domain Dedication.
Intent
Measure the execution time of a unit of code.
Description
We introduce the type alias clock on line 5 such that it refers to
the std::chrono::steady_clock type.
This type represents a monotonic (always increasing) clock.
Before and after the task that we wish to time (line 7 and line 9
respectively), we call the static member function clock::now
which gives us a
std::chrono::time_point representing the
point in time at which it was called. By subtracting the start
time point from the end time point on line 11, we get a
std::chrono::duration representing the
time taken between these time points and, therefore, the execution
time of our task.
We can access the value of a std::chrono::duration by calling its
count member function. The units of the std::chrono::duration
are determined by the clock it came from, but it can be casted to
another std::duration with different units with the
std::chrono::duration_cast
function (or implicitly, if the units are exactly divisible).
