The current way of calculating the CPU utilization rate is not accurate. The accounting system only works In the interval of two ticks. However, a process can give up the CPU before the tick ending.

This can be fixed by counting the idel time via the scheduler. We can use the sum_exe_runtime of the idle process of each CPU to calculate the the CPU utilization rate. The idle time of each CPU is given in the /proc/stat2 file. An example of using this file is also attached.

Hongyu Li (2): eulerfs: add the /proc/stat2 file tools: add a tool to calculate the CPU utilization rate

fs/proc/Kconfig | 7 +++ fs/proc/Makefile | 1 + fs/proc/stat2.c | 91 +++++++++++++++++++++++++++++++++++++ kernel/sched/cputime.c | 34 ++++++++++++++ kernel/sched/idle.c | 38 ++++++++++++++++ tools/accounting/Makefile | 2 +- tools/accounting/idle_cal.c | 91 +++++++++++++++++++++++++++++++++++++ 7 files changed, 263 insertions(+), 1 deletion(-) create mode 100644 fs/proc/stat2.c create mode 100644 tools/accounting/idle_cal.c