For that you will have to use chronometers.
Measure wall clock time in c.
The clock function tells how much wall clock time has passed since the crt initialization during process start.
End clock.
Wtime a c function which returns a reading of the wall clock time.
Int clock gettime clockid t clock id struct timespec tp.
Using clock gettime function in c c.
The obvious one is gettimeofday.
Do the work.
For parallel programming the important thing to measure is the elapsed wallclock time.
As it turns out c has many functions available to get the current time.
This can be found by subtracting an initial reading of the wallclock time from a final one.
In all multivalue basic languages you can use the time function to return the number of seconds from midnight.
For example if the cpu is shared by other processes std clock time may advance slower than wall clock.
Following is a sample c program where we measure time taken by fun.
Include sys time h int gettimeofday struct timeval restrict tp void restrict tzp.
Prototype syntax.
The system s notion of the current greenwich time and the current time zone.
The function fun waits for enter key press to terminate.
The clock gettime function gets the current time of the clock specified by clock id and puts it into the buffer pointed to by tp.
Note that this function does not strictly conform to iso c which specifies net cpu time as the return value.
Calculating the elapsed wall clock time of a program is helpful to determine how much time it actually takes for a program to complete.
There are a lot of ways to measure time in computer science but as a general rule of thumb you should always use a clock that measures the elapsed real time or wall time.
Cpu time used double end start clocks per sec.
The openmp system provides a function used as follows.
To obtain cpu times use the win32 getprocesstimes function.
Std clock time may advance faster or slower than the wall clock depending on the execution resources given to the program by the operating system.
Tp parameter points to a structure containing atleast the following members.
The gettimeofday function returns the wall clock time elapsed since the epoch and store it in the timevalstructure expressed as seconds and microseconds.