* 25% cpu usage during idle
@ 2010-07-28 19:26 Bastian Blank
2010-07-28 19:34 ` Jeremy Fitzhardinge
2010-09-23 0:12 ` Jeremy Fitzhardinge
0 siblings, 2 replies; 3+ messages in thread
From: Bastian Blank @ 2010-07-28 19:26 UTC (permalink / raw)
To: Jeremy Fitzhardinge, xen-devel
A new pvops kernel (78b55f90e72348e231092dbe3e50ac7414b9e1af) needs around 25%
cpu while being idle with 32 guest domains in event and ksoftirq kernel
threads:
| 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
--
Change is the essential process of all existence.
-- Spock, "Let That Be Your Last Battlefield", stardate 5730.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 25% cpu usage during idle
2010-07-28 19:26 25% cpu usage during idle Bastian Blank
@ 2010-07-28 19:34 ` Jeremy Fitzhardinge
2010-09-23 0:12 ` Jeremy Fitzhardinge
1 sibling, 0 replies; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2010-07-28 19:34 UTC (permalink / raw)
To: Bastian Blank, xen-devel
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:
My guesses at filling in the blanks:
* this is dom0
* this is a 12 core host
* you mean 25% of one core, not 25% of all available cpu power
* no other dom0 processes are using any cpu time
* the guest domains are PV, with one disk and net device each
* they're all idle, with no cpu, net or disk traffic
* this behaviour is new to this kernel
Is that correct?
What was the last kernel which didn't have this behaviour?
Does it get better or worse when you have fewer vcpus in dom0?
How do the interrupt counts in /proc/interrupts change?
Thanks,
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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 25% cpu usage during idle
2010-07-28 19:26 25% cpu usage during idle Bastian Blank
2010-07-28 19:34 ` Jeremy Fitzhardinge
@ 2010-09-23 0:12 ` Jeremy Fitzhardinge
1 sibling, 0 replies; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2010-09-23 0:12 UTC (permalink / raw)
To: Bastian Blank, xen-devel
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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-07-28 19:26 25% cpu usage during idle Bastian Blank
2010-07-28 19:34 ` Jeremy Fitzhardinge
2010-09-23 0:12 ` Jeremy Fitzhardinge
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