[Coco] CPU utilization calculation in NitrOS-9

[Alex Evans]

On a modern linux system, if you have a 4 core system with 4 cpu bound
processes, you will get a load of 4. To be honest, reporting the
average load oc the cores as opposed to the sum of the load is better
in a lot of ways.

On Tue, Jan 26, 2021 at 3:34 AM Johann Klasek <johann+coco at klasek.at> wrote:
>
> On Mon, Jan 25, 2021 at 11:22:52PM -0500, Alex Evans wrote:
> > Just waiting, not waiting for I/O. If you run completely CPU bound
> > processes, they will push up the load, but processes that are delayed
> > by I/O can also push up the load.
>
> It's an interpretation of Linux that counts uninterruptible device wait
> processes as "to run" processes in context of load evaluation. This is
> not the way all Unix system are calculating the load, especially
> historically. E.g. Solaris, Ultrix, HPUX all etc. all consider just the
> processes in ready (to run) state. In the days we switched from Solaris
> to Linux many were wondering why Linux servers shows that much load. The
> Linux server's hardware (except the CPU) had not that throughput of a
> Solaris HW, slower disk leads to more device waits which drove the load
> up.
> What I want to say is: Don't think that only what Linux does is "Unix".
>
> The load shows the contention of a system. Even there are multiple cores
> or CPUs, a load of 1 means that all CPUs/cores are utilized with a
> running process. If a 4 core machine has load 1, 4 processes are currently
> running, no other process is ready to run (just waiting on I/O or a
> some other "event").
>
> Johann
>
>
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