MAN 1 UTIME HOW TO

When I now calculate this sum and divide it by the total amount of jiffies in the analyzed interval, I would assume the formula for one process to be processCPUUsage = ((process_utime_aft - process_utime_bef) + (process_stime_aft - process_stime_bef)) /

MAN 1 UTIME HOW TO

((user_aft - user_bef) + (nice_aft - nice_bef) + (system_aft - system_bef) + (idle_aft - idle_bef)) * 100 %Īccording to How to calculate the CPU usage of a process by PID in Linux from C? the used jiffies for a single process can be calculated by adding utime and stime from /proc/$/stat (column 14 and 15 in this file). The formula would be totalCPUUsage = ((user_aft - user_bef) + (nice_aft - nice_bef) + (system_aft - system_bef)) / If you now sample the values at two points in time and compare the values for user, nice, system and idle at the two time points, you can calculate the average CPU usage in this interval. For now the CPU I am using is multi-cored (2 cores).Īccording to How to determine CPU and memory consumption from inside a process? it is possible to calculate all 'jiffies' available in the system since startup using the values for 'cpu' in /proc/stat. My assumption would be that the sum of all process CPU times would be equal to the total value for the whole CPU.

The programm should be designed and implemented in C++. In the Linux DLL 4.4.1 libraries, utimes is just a wrapper for utime: tvp0. If buf is NULL, then the access and modification. If buf is NULL, then the access and modification times of the file are set to the current time.

utime changes the access and modification times of the inode specified by filename to the actime and modtime fields of buf respectively. utime changes the access and modification times of the inode specified by filename to the actime and modtime fields of buf respectively. I need to calculate the overall CPU usage of my Linux device over some time (1-5 seconds) and a list of processes with their respective CPU usage times. Man Pages : UTIME NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS.

Man 1 utime