I tried to calculate the % of CPU usage in linux via the /proc/stat kernel interface.
I read the first "cpu" line twice in /proc/stat with an interval of 0.5 seconds and then save the output into two ArrayLists (arrayStats = [user, nice, system, idle]).

I want to calculate CPU time consumption of a particular process in system mode and user mode using statistics present in /proc/

There are two fields utime and stime in /proc//stat file, whose documentation says

utime: Amount of time that this process has been scheduled in user mode
stime: Amount of time that this process has been scheduled in kernel(system) mode

I am calculating CPU time con

I am about to find out how a specific process, in C, loads the CPU over a certain time frame.
The process may switch processor core during runtime, therefore
I need to handle that too.

I am bit confuse between cpu usage and cpu load, Can anyone please explain me the basic difference between them and what formula should we use to calculate them on Linux?
I am accessing /proc/stat file to calculate cpu usage.

Hi.

For an homework, I have to simulate some part of the PS function.

My program samples /proc data in order to get statistic about the CPU usage of the system.
I sample both /proc/stat and calculate the statistics delta (in interval of 1 second),
and I also sample the process /proc/pid/stat user ticks and system ticks.
This is an exmaple of log from my system:

From /proc/stat(total System)- UserTicksDelta: 9, niceTicksDelta: 0, SystemTicksDelta: 3, IrqTicksDelta:

My program samples /proc data in order to get statistic about the CPU usage of the system. I sample both /proc/stat and calculate the statistics delta (in interval of 1 second), and I also sample the process /proc/pid/stat user ticks and system ticks.

Is there any C API to calculate per CPU load? /proc/loadavg gives the CPU average load for all available CPUs and /proc/stat doesn't mention anything about active processes per CPU.

How can I obtain the load per CPU?

I guess the question is, could I somehow calculate the CPU utilization percentage just by reading the /proc/stat once?

# head -1 /proc/stat
cpu 67891300 39035 6949171 2849641614 118251644 365498 2341854 0

I am thinking about summarizing the columns except the IOWait (I was reading somewhere that it is counted in the idle) and that would give me the 100% and each individual column could be turn