Collected cpu time counts
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
utime
time spent in user mode, in cputime_t units
stime
time spent in kernel mode, in cputime_t units
sum_exec_runtime
total time spent on the CPU, in nanoseconds
This is an extension of struct cputime that includes the total runtime spent by the task from the scheduler point of view.
As a result, this structure groups together three kinds of CPU time that are tracked for threads and thread groups. Most things considering CPU time want to group these counts together and treat all three of them in parallel.