usage accounting inconsistencies

[Danial Thom]

--- Danial Thom <danial_thom at xxxxxxxxx> wrote:

> When applying a constant load (v1.5.3-PREVIEW),
> usage is categorized differently in UP mode
> than
> n SMP model. 
> 
> In UP Mode
> 
> CPU-0 state:   0.00% user,   0.00% nice,  0.00%
> sys,   32.14% intr,  67.86% idle
> 
> In SMP mode:
> 
> CPU-0 state:   0.00% user,   0.00% nice, 
> 31.27%
> sys,   0.00% intr,  68.73% idle
> CPU-1 state:   0.00% user,   0.00% nice,  
> 0.00%
> sys,   1.56% intr,  98.44% idle
> 
> Is this to be expected? It seems to me that if
> the handoff to the receive queue marks the end
> of
> interrupt processing in SMP mode (I assume),
> that
> it also should be measured that way in UP mode.
> It would be nice if they were the same so one
> could get a better handle on the efficiencies
> or
> inefficiencies of the SMP processing.
> 
> DT
:
:  Nearly all interrupts are run on cpu 0.  This 
: isn't going to change
: until the APIC interrupt routing infrastructure

: is rewritten.
:
: Matt

If thats the case, then why is cpustat showing
'intr' usage only on CPU-1?

DT

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