[Xen-devel] Re: 25% cpu usage during idle

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

 On 07/28/2010 12:26 PM, Bastian Blank wrote:
> A new pvops kernel (78b55f90e72348e231092dbe3e50ac7414b9e1af) needs around 25%
> cpu while being idle with 32 guest domains in event and ksoftirq kernel
> threads:

I've never seen it that high, but it looks like something in the pty
layer will spin waking up at HZ rate if you have buffered console output
pending.  If you do x[lm] console for each domain you can quieten it
down.  Does that match what you're seeing?

You can also see it with powertop.

    J

> | root         4  3.6  0.0      0     0 ?        S    21:08   0:26 
> [ksoftirqd/0]
> | root         7  8.6  0.0      0     0 ?        S    21:08   1:03 
> [ksoftirqd/1]
> | root        10  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/2]
> | root        13  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/3]
> | root        16  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/4]
> | root        19  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/5]
> | root        22  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/6]
> | root        25  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/7]
> | root        28  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/8]
> | root        31  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/9]
> | root        34  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/10]
> | root        37  0.0  0.0      0     0 ?        S    21:08   0:00 
> [ksoftirqd/11]
> | root        39  1.3  0.0      0     0 ?        S    21:08   0:09 [events/0]
> | root        40 14.0  0.0      0     0 ?        S    21:08   1:44 [events/1]
> | root        41  0.0  0.0      0     0 ?        S    21:08   0:00 [events/2]
> | root        42  0.0  0.0      0     0 ?        S    21:08   0:00 [events/3]
> | root        43  0.1  0.0      0     0 ?        S    21:08   0:00 [events/4]
> | root        44  0.0  0.0      0     0 ?        S    21:08   0:00 [events/5]
> | root        45  0.0  0.0      0     0 ?        S    21:08   0:00 [events/6]
> | root        46  0.0  0.0      0     0 ?        S    21:08   0:00 [events/7]
> | root        47  0.0  0.0      0     0 ?        S    21:08   0:00 [events/8]
> | root        48  0.0  0.0      0     0 ?        S    21:08   0:00 [events/9]
> | root        49  0.0  0.0      0     0 ?        S    21:08   0:00 [events/10]
> | root        50  0.0  0.0      0     0 ?        S    21:08   0:00 [events/11]
>
> Bastian
>


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