[Powertop] Query: Weird Output values: Percentage over 100%

[Powertop] Query: Weird Output values: Percentage over 100%

[viresh kumar]

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Hi,

I am noticing something strange in powertop reports.
When i run powertop with following parameters:

powertop -t 120 --html

I see following in summary section

Power Consumption Summary

0.1 wakeups/second, 0.0 GPU ops/second, 0.0 VFS ops/sec, 0.0 GFX
wakes/sec and 5375.4% CPU use

Usage	Events/s	Category	Description
2693%	 0.07	Timer	tick_sched_timer
2680%	 0.00	Timer	ehci_watchdog
0.6%	 0.00	Interrupt	[7] sched(softirq)
0.2%	 0.00	Interrupt	[1] timer(softirq)
0.2%	 0.00	Interrupt	[29] twd
0.1%	 0.00	kWork	pm_runtime_work
0.1%	 0.00	Timer	led_heartbeat_function
0.1%	 0.00	Interrupt	[9] RCU(softirq)
0.1%	 0.00	Interrupt	[57] OMAP DISPC
0.1%	 0.00	Process	rsyslogd -c5


How is percentage over 100 %...

System Info:

PowerTOP Version	v2.0
Kernel Version	Linux version 3.4.0-01820-gcc96f22
(viresh(a)blr-linut-001) (gcc version 4.7.1 20120514 (prerelease)
(crosstool-NG linaro-1.13.1-2012.05-20120523 - Linaro GCC 2012.05) )
#5 SMP PREEMPT Tue Aug 28 12:44:52 IST 2012
System Name	
CPU Information	2x
OS Information	

Running on ARM: Panda Board.

--
viresh

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[viresh kumar]

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Ping!!

On Wed, Aug 29, 2012 at 1:39 PM, viresh kumar <viresh.kumar(a)linaro.org> wrote:
> Hi,
>
> I am noticing something strange in powertop reports.
> When i run powertop with following parameters:
>
> powertop -t 120 --html
>
> I see following in summary section
>
> Power Consumption Summary
>
> 0.1 wakeups/second, 0.0 GPU ops/second, 0.0 VFS ops/sec, 0.0 GFX
> wakes/sec and 5375.4% CPU use
>
> Usage   Events/s        Category        Description
> 2693%    0.07   Timer   tick_sched_timer
> 2680%    0.00   Timer   ehci_watchdog
> 0.6%     0.00   Interrupt       [7] sched(softirq)
> 0.2%     0.00   Interrupt       [1] timer(softirq)
> 0.2%     0.00   Interrupt       [29] twd
> 0.1%     0.00   kWork   pm_runtime_work
> 0.1%     0.00   Timer   led_heartbeat_function
> 0.1%     0.00   Interrupt       [9] RCU(softirq)
> 0.1%     0.00   Interrupt       [57] OMAP DISPC
> 0.1%     0.00   Process rsyslogd -c5
>
>
> How is percentage over 100 %...
>
> System Info:
>
> PowerTOP Version        v2.0
> Kernel Version  Linux version 3.4.0-01820-gcc96f22
> (viresh(a)blr-linut-001) (gcc version 4.7.1 20120514 (prerelease)
> (crosstool-NG linaro-1.13.1-2012.05-20120523 - Linaro GCC 2012.05) )
> #5 SMP PREEMPT Tue Aug 28 12:44:52 IST 2012
> System Name
> CPU Information 2x
> OS Information
>
> Running on ARM: Panda Board.
>
> --
> viresh

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Sergey Senozhatsky]

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On (09/03/12 12:24), viresh kumar wrote:
> Ping!!
> 
> On Wed, Aug 29, 2012 at 1:39 PM, viresh kumar <viresh.kumar(a)linaro.org> wrote:
> > Hi,
> >
> > I am noticing something strange in powertop reports.
> > When i run powertop with following parameters:
> >
> > powertop -t 120 --html
> >
> > I see following in summary section
> >
> > Power Consumption Summary
> >
> > 0.1 wakeups/second, 0.0 GPU ops/second, 0.0 VFS ops/sec, 0.0 GFX
> > wakes/sec and 5375.4% CPU use
> >
> > Usage   Events/s        Category        Description
> > 2693%    0.07   Timer   tick_sched_timer
> > 2680%    0.00   Timer   ehci_watchdog
> > 0.6%     0.00   Interrupt       [7] sched(softirq)
> > 0.2%     0.00   Interrupt       [1] timer(softirq)
> > 0.2%     0.00   Interrupt       [29] twd
> > 0.1%     0.00   kWork   pm_runtime_work
> > 0.1%     0.00   Timer   led_heartbeat_function
> > 0.1%     0.00   Interrupt       [9] RCU(softirq)
> > 0.1%     0.00   Interrupt       [57] OMAP DISPC
> > 0.1%     0.00   Process rsyslogd -c5
> >
> >

Hi, sorry, 

well, we've seen this one before. the reasons are still unclear.

	-ss


> > How is percentage over 100 %...
> >
> > System Info:
> >
> > PowerTOP Version        v2.0
> > Kernel Version  Linux version 3.4.0-01820-gcc96f22
> > (viresh(a)blr-linut-001) (gcc version 4.7.1 20120514 (prerelease)
> > (crosstool-NG linaro-1.13.1-2012.05-20120523 - Linaro GCC 2012.05) )
> > #5 SMP PREEMPT Tue Aug 28 12:44:52 IST 2012
> > System Name
> > CPU Information 2x
> > OS Information
> >
> > Running on ARM: Panda Board.
> >
> > --
> > viresh
> _______________________________________________
> PowerTop mailing list
> PowerTop(a)lists.01.org
> https://lists.01.org/mailman/listinfo/powertop
> 

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Arjan van de Ven]

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>> Running on ARM: Panda Board.

I wonder if the perf data is somehow incorrect on your platform.
powertop depends on correct timestamps for example.

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Sergey Senozhatsky]

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On (09/03/12 10:37), Arjan van de Ven wrote:
> >> Running on ARM: Panda Board.
> 
> I wonder if the perf data is somehow incorrect on your platform.
> powertop depends on correct timestamps for example.
> 
> 

I was thinking about this. Could it be possible that we lose
some perf samples? E.g. we have start, but no end timestamps.


	-ss

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Arjan van de Ven]

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On 9/3/2012 10:57 AM, Sergey Senozhatsky wrote:
> On (09/03/12 10:37), Arjan van de Ven wrote:
>>>> Running on ARM: Panda Board.
>>
>> I wonder if the perf data is somehow incorrect on your platform.
>> powertop depends on correct timestamps for example.
>>
>>
> 
> I was thinking about this. Could it be possible that we lose
> some perf samples? E.g. we have start, but no end timestamps.

shouldn't... the buffers are quite large....

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Igor Zhbanov]

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Arjan van de Ven wrote:

> shouldn't... the buffers are quite large....

By the way, I just curious, why events processing are limited to 5000?
I mean the PowerTOP has f half-megabyte buffer for each type of events
but wishes to process only 5000 even if data is there?

void perf_event::process(void *cookie)
{
...
	while (pc->data_tail != pc->data_head && i++ < 5000) {
...

In the case of many cores sched:switch will be fired at least CONFIG_HZ * nr_cpus
times per second (as I understand), and that could easily be larger than 5000.
Especially when we measuring for several seconds.

-- 
Best regards,
Igor Zhbanov,
Expert Software Engineer,
phone: +7 (495) 797 25 00 ext 3806
e-mail: i.zhbanov(a)samsung.com

ASWG, Moscow R&D center, Samsung Electronics
12 Dvintsev street, building 1
127018, Moscow, Russian Federation

Re: [Powertop] Query: Weird Output values: Percentage over 100%

[Sergey Senozhatsky]

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On (09/04/12 11:30), Igor Zhbanov wrote:
> Arjan van de Ven wrote:
> 
> >shouldn't... the buffers are quite large....
> 
> By the way, I just curious, why events processing are limited to 5000?
> I mean the PowerTOP has f half-megabyte buffer for each type of events
> but wishes to process only 5000 even if data is there?
> 
> void perf_event::process(void *cookie)
> {
> ...
> 	while (pc->data_tail != pc->data_head && i++ < 5000) {
> ...
> 
> In the case of many cores sched:switch will be fired at least CONFIG_HZ * nr_cpus
> times per second (as I understand), and that could easily be larger than 5000.
> Especially when we measuring for several seconds.
> 

good spot.
Also interested if we will fit all perf samples on (e.g.) loaded 64 core system.

	-ss