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#1 2010-04-30 20:16:21

orschiro
Member
Registered: 2009-06-04
Posts: 2,136
Website

powertop how to reduce wakeups

Hello guys,

I'm running a minimal arch on my Thinkpad SL500. I looked at my ressources with powertop and top and it looks fine I'd say. But nevertheless I have a very high wakeup rate.

Here's my powertop extract.

[root@thinkpad robert]# powertop -d
PowerTOP 1.12   (C) 2007, 2008 Intel Corporation 

Sammle Daten für 15 Sekunden 


Cn                 Verweildauer
C0 (Prozessor läuft)    ( 9,9%)
zyklisches AbfraC1 mwait          0,6ms ( 0,0%)
C1 mwait          0,1ms ( 0,0%)
C3 mwait          1,4ms (90,0%)
P-States (Frequenzen)
Turbo-Modus     1,4%
  2,00 GHz     0,0%
  1,60 GHz     0,6%
  1200 MHz     0,1%
   800 MHz    97,8%
Aufwachen pro Sekunde : 631,7   Intervall: 15,0s
Keine ACPI Stromverbrauch-Schätzung verfügbar
Häufigste Ursachen für das Aufwachen:
  24,5% (195,3)   [extra timer interrupt]
  22,9% (182,2)   firefox
  21,0% (166,8)   [kernel scheduler] Load balancing tick
  17,8% (141,7)   [iwlagn] <interrupt>
   5,9% ( 46,9)   [hda_intel] <interrupt>
   1,5% ( 12,3)   skype
   1,3% ( 10,2)   [ahci] <interrupt>
   1,2% (  9,7)   [acpi] <interrupt>
   1,0% (  8,0)   [kernel core] usb_hcd_poll_rh_status (rh_timer_func)
   0,6% (  4,9)   [kernel core] hrtimer_start (tick_sched_timer)
   0,6% (  4,8)   klensl_hkeyd
   0,4% (  3,1)   [kernel core] sk_reset_timer (tcp_delack_timer)
   0,3% (  2,6)   X
   0,3% (  2,3)   [Rescheduling interrupts] <kernel IPI>
   0,1% (  1,0)   [kernel core] __enqueue_rt_entity (sched_rt_period_timer)
   0,1% (  1,0)   sleep
   0,1% (  0,9)   kcryptd
   0,1% (  0,7)   hald-addon-stor
   0,1% (  0,6)   [TLB shootdowns] <kernel IPI>
   0,0% (  0,2)   init
   0,0% (  0,1)   flush-254:3
   0,0% (  0,1)   [kernel core] rtl8169_phy_timer (rtl8169_phy_timer)
   0,0% (  0,1)   crond
   0,0% (  0,1)   PS/2 keyboard/mouse/touchpad interrupt
   0,0% (  0,1)   flush-254:1
   0,0% (  0,1)   [kernel core] cfq_completed_request (cfq_idle_slice_timer)
   0,0% (  0,1)   [kernel core] arm_supers_timer (sync_supers_timer_fn)
   0,0% (  0,1)   [kernel core] add_timer (sta_info_cleanup)
   0,0% (  0,1)   [kernel core] blk_rq_timed_out_timer (blk_rq_timed_out_timer)
   0,0% (  0,1)   hald

An audio device is active 100,0% of the time:
hwC0D0 Conexant CX20561 (Hermosa) 

Ein USB Gerät ist 100,0% der Zeit aktiv:
USB Gerät  5-1 : ThinkPad Bluetooth with Enhanced Data Rate II (Lenovo Computer Corp)

Vorschlag: Aktivieren Sie USB-Autosuspend für Nicht-Eingabegeräte inden Sie die U-Taste betätigen


Vorschlag: Aktivieren Sie das SATA ALPM link power Management mit:   echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
oder durch betätigen der S-Taste.

Vorschlag: Aktivieren Sie mit folgendem Befehl die WLAN Stromsparfunktionen:
  iwconfig wlan0 power timeout 500ms
Dadurch verringert sich die WLAN-Geschwindigkeit etwas, spart aber Strom.

aktuelle "USB suspend" Statistiken
Name des aktiven Gerätes
100,0%  USB Gerät  7-1 : USB Mouse (Logitech)
100,0%  USB Gerät  5-1 : ThinkPad Bluetooth with Enhanced Data Rate II (Lenovo Computer Corp)
100,0%  USB Gerät  2-5 : CNF7237&CNF7238 (Chicony Electronics Co., Ltd.)
  0,0%  USB Gerät usb8 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
100,0%  USB Gerät usb7 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
  0,0%  USB Gerät usb6 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
100,0%  USB Gerät usb5 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
  0,0%  USB Gerät usb4 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
  0,0%  USB Gerät usb3 : UHCI Host Controller (Linux 2.6.33-ARCH uhci_hcd)
100,0%  USB Gerät usb2 : EHCI Host Controller (Linux 2.6.33-ARCH ehci_hcd)
  0,0%  USB Gerät usb1 : EHCI Host Controller (Linux 2.6.33-ARCH ehci_hcd)

Recent audio activity statistics
Name des aktiven Gerätes
100,0%  hwC0D0 Conexant CX20561 (Hermosa) 
  0,0%  hwC0D2 Intel G45 DEVCTG 

Recent SATA AHCI link activity statistics
Active  Partial Slumber Device name

It is in german but I hope you can identify the main points. There are three processes that produce a high wakeup besides Firefox. What are they in special?

 24,5% (195,3)   [extra timer interrupt]
  22,9% (182,2)   firefox
  21,0% (166,8)   [kernel scheduler] Load balancing tick
  17,8% (141,7)   [iwlagn] <interrupt>

And why the hell does my wireless connection produce such a high wakeup?

Thank you for your tips. smile

Last edited by orschiro (2010-04-30 20:16:58)

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#2 2010-05-01 09:54:47

karol
Archivist
Registered: 2009-05-06
Posts: 25,440

Re: powertop how to reduce wakeups

I'm not a guru, but I think the computers and apps (kernel included) were made to work, not idle, so the default settings will cause some wakeups because all your software is so eager to do some work for you :-) If a non-hybrid gas(oline)-powered car has its engine running but doesn't move (in an outdoor parking lot, in a traffic jam etc.) it will use gas make noise etc.
Do you have some problems w/ your battery? If not, then just focus on your work, or have fun and don't worry about the kernel scheduler - it produces high wakeups here too.

> And why the hell does my wireless connection produce such a high wakeup?
Idk, I use a wired one.

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#3 2010-05-01 19:29:37

orschiro
Member
Registered: 2009-06-04
Posts: 2,136
Website

Re: powertop how to reduce wakeups

Hello karol,

all in all I have no problems at all but want to optimize my system a little bit. Hence I asked the professionals for advice what they would change.

Regards

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#4 2010-05-01 19:51:10

karol
Archivist
Registered: 2009-05-06
Posts: 25,440

Re: powertop how to reduce wakeups

"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil"
Donald Knuth

You want your PC to work the way your cellphone does, but the current PCs are not always-on devices and thus follow a different design.

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#5 2010-05-01 21:16:56

crocowhile
Member
Registered: 2009-10-18
Posts: 56

Re: powertop how to reduce wakeups

about the first two lines:
1. You could try passing to chrome. it's less resource intensive than firefox and very mature now. I was a firefox user for years and just made the switch to chrome. best thing i have done this week.
2. you can try recompiling your kernel with a different ticking frequency. Default is 300, you can move to 250 or 100. Unless you do a lot of multimedia editing it won't make a difference.

gg@majorana:~$ zcat /proc/config.gz | grep CONFIG_HZ
# CONFIG_HZ_100 is not set
# CONFIG_HZ_250 is not set
CONFIG_HZ_300=y
# CONFIG_HZ_1000 is not set
CONFIG_HZ=300

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