[PATCH 0/2][KVM] guest time accounting

[Laurent Vivier <Laurent.Vivier@bull.net>]

The aim of these two patches is to measure the CPU time used by a virtual
machine. All comments are welcome... I'm not sure it's the good way to do that.

[PATCH 1/2] introduce a new field, "guest", in cpustat to store the time used by
the CPU to run virtual CPU. Modify /proc/stat to display this new field.

[PATCH 2/2] modify account_system_time() to add cputime to cpustat->guest if we
are running a VCPU. We add this cputime to  cpustat->user instead of
cpustat->system because this part of KVM code is in fact user code although it
is executed in the kernel. We duplicate VCPU time between guest and user to
allow an unmodified "top(1)" to display correct value. A modified "top(1)" is
able to display good cpu user time and cpu guest time by subtracting cpu guest
time from cpu user time.

Signed-Off-by: Laurent Vivier <Laurent.Vivier@bull.net>
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