Xen devel - Aug 2005 - [PATCH] Fix domain CPU time calculation to count all VCPU times correctly

Currently, the getdomaininfo function (used to fill in a
dom0_getdomaininfo_t for a domain) calculates a domain''s total CPU time
from its VCPU times using the code:
        if ( v->cpu_time > cpu_time )
            cpu_time += v->cpu_time;
This causes a VCPU''s time to only be counted if it is greater than the
current total; so if VCPU0 has 10 seconds and VCPU1 has 5, the total
will be 10, but if VCPU0 has 5 and VCPU10 has 10, the total will be 15.
Is there a reason for this behavior?  It seems more useful and intuitive
to always total the VCPU times to obtain the CPU time.

The attached patch removes the conditional, so that all VCPU times for a
domain are always totaled to obtain the CPU time for that domain.

Signed-off-by: Josh Triplett <josht@us.ibm.com>

- Josh Triplett



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On 8 Aug 2005, at 19:22, Josh Triplett wrote:
> This causes a VCPU''s time to only be counted if it is greater than
the
> current total; so if VCPU0 has 10 seconds and VCPU1 has 5, the total
> will be 10, but if VCPU0 has 5 and VCPU10 has 10, the total will be 15.
> Is there a reason for this behavior?  It seems more useful and 
> intuitive
> to always total the VCPU times to obtain the CPU time.
I think we used to return the highest VCPU time as domain time. Someone 
decided to instead sum across all VCPU times, but I guess forgot to 
remove the conditional. :-)

  -- Keir


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