We have a few linux servers with kernel.hz_timer = 0 that run under
z/VM.  I'm not sure how that patch factors into things below.

I know the linux CPU numbers are relative to the CPU z/VM gives the
dispatched guest, but how about idle ticks/jiffies from the linux
perspective?  The VM accounting records show that we usually have CPU to
spare, and except during things like compiles, the guests are usually
more idle than not from the linux perspective.

So if the VM records show that a guest used 10% of the total CPU, and a
before/after of /proc/stat shows that half of the ticks were spent in
the "idle task", did the guest truly only need 5%?  As more guests use
CPU, I'd expect that guest's usage to drop below 10% from z/VM's
perspective, and the "idle jiffies" to drop from linux's perspective,
but the user/nice/system numbers would not change much assuming similar
work was being done, and we aren't always running at 100%.  Does that
sound about right?

~ Daniel

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