Messages in this thread |  | | From | (H. Peter Anvin) | Subject | Re: CPU Utilization | Date | 30 Jun 1996 22:40:51 GMT |
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Followup to: <199606281942.VAA19665@informatik.uni-koblenz.de> By author: Systemkennung Linux <linux@mailhost.uni-koblenz.de> In newsgroup: linux.dev.kernel > > Hi, > > > What's the best way to get the instantaneous CPU utilization? I am > > trying to build-a-better-CPUMeter and I want a routine I can call about 4 > > times per second with little CPU overhead... > > Under Linux you can use the values in /proc/uptime. The first of the > numbers is the number of seconds since the system was rebooted, the second > the number of seconds idle time that were burned in the swapper process. > It should be obvious how to compute the CPU usage % from these numbers. > > Or use the numbers from /proc/loadavg if they should fit your purpose > better. > > It isn't really required to measure the CPU usage yourself unless you want > to port this program to non-Linux operating systems which apparently still > exist :-) >
The *instantaneous* CPU usage, when measured, is always 100% since your measuring process is obviously running at that time, the CPU is being utilized... hence, it is a useless metric, and the reason a decaying average is used instead.
-hpa
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