[announce] Intel announces the PowerTOP utility for Linux

[announce] Intel announces the PowerTOP utility for Linux

[Arjan van de Ven]

What's eating the battery life of my laptop? Why isn't it many more 
hours? Which software component causes the most power to be burned? 
These are important questions without a good answer... until now.

The Linux 2.6.21 kernel introduces the so called tickless-idle 
feature. This feature allows the processor to be really idle for long 
periods of time, rather than having to wake up every millisecond for 
the timer tick. Current processors save a lot of power if they are 
idle for long periods, which translates into a longer battery life for 
your laptop, or a lower energy bill for your datacenter. However, a 
Linux system consists of more software than just the kernel, and there 
are many tunables involved. It's not easy to see what is going on, and 
as a result the behavior is sometimes far from optimal, and a lot of 
power is wasted.

Intel is proud to announce the PowerTOP tool 
(http://www.linuxpowertop.org), a program that collects the various 
pieces of information from your system and presents an overview of how 
well your laptop is doing in terms of power savings. In addition, 
PowerTOP will provide an indication of which tunables and software 
components are the biggest offenders in slurping up your battery time. 
PowerTOP will update it's display frequently so that you can directly 
see the impact of any changes you are making.

A typical Linux distribution has many components that wake the 
processor up frequently for no good reason. In our testing with 
PowerTOP, we have seen many cases where with some simple fixes, the 
battery life of typical laptops was increased by one hour or more!

We are providing fixes for several of the issues we identified, and we 
encourage the Linux community to help us in this quest to get the 
maximum battery life out of your (hopefully Intel based) laptops. Try 
the PowerTOP tool, join the mailing list or the IRC channel and 
provide feedback, problem reports or fixes!

Website:      http://www.linuxpowertop.org
IRC:          irc.oftc.net    #powertop channel
Mailing list: http://www.bughost.org/mailman/listinfo/power

Re: [announce] Intel announces the PowerTOP utility for Linux

[Matt Mackall]

On Fri, May 11, 2007 at 04:07:18PM -0700, Arjan van de Ven wrote:
> 
> What's eating the battery life of my laptop? Why isn't it many more 
> hours? Which software component causes the most power to be burned? 
> These are important questions without a good answer... until now.

I get:

No detailed statistics available; please enable the CONFIG_TIMER_STATS
kernel option

with:

$ zgrep STATS /proc/config.gz 
# CONFIG_TASKSTATS is not set
# CONFIG_SCHEDSTATS is not set
CONFIG_TIMER_STATS=y

-- 
Mathematics is the supreme nostalgia of our time.

Re: Re: [announce] Intel announces the PowerTOP utility for Linux

[Jose Celestino]

Words by Matt Mackall [Fri, May 11, 2007 at 07:17:19PM -0500]:
> On Fri, May 11, 2007 at 04:07:18PM -0700, Arjan van de Ven wrote:
> > 
> > What's eating the battery life of my laptop? Why isn't it many more 
> > hours? Which software component causes the most power to be burned? 
> > These are important questions without a good answer... until now.
> 
> I get:
> 
> No detailed statistics available; please enable the CONFIG_TIMER_STATS
> kernel option
> 

Must run as root (rw to /proc/timer_stats is needed).

-- 
Jose Celestino
----------------------------------------------------------------
http://www.msversus.org/     ; http://techp.org/petition/show/1
http://www.vinc17.org/noswpat.en.html
----------------------------------------------------------------
"And on the trillionth day, Man created Gods." -- Thomas D. Pate

Re: Re: [announce] Intel announces the PowerTOP utility for Linux

[Matt Mackall]

On Sat, May 12, 2007 at 02:40:52AM +0100, Jose Celestino wrote:
> Words by Matt Mackall [Fri, May 11, 2007 at 07:17:19PM -0500]:
> > On Fri, May 11, 2007 at 04:07:18PM -0700, Arjan van de Ven wrote:
> > > 
> > > What's eating the battery life of my laptop? Why isn't it many more 
> > > hours? Which software component causes the most power to be burned? 
> > > These are important questions without a good answer... until now.
> > 
> > I get:
> > 
> > No detailed statistics available; please enable the CONFIG_TIMER_STATS
> > kernel option
> > 
> 
> Must run as root (rw to /proc/timer_stats is needed).

That file doesn't exist, despite CONFIG_TIMER_STATS being in
/proc/config.gz.

-- 
Mathematics is the supreme nostalgia of our time.

Re: Re: Re: [announce] Intel announces the PowerTOP utility for Linux

[Jose Celestino]

Words by Matt Mackall [Fri, May 11, 2007 at 09:39:05PM -0500]:
> On Sat, May 12, 2007 at 02:40:52AM +0100, Jose Celestino wrote:
> > Words by Matt Mackall [Fri, May 11, 2007 at 07:17:19PM -0500]:
> > > On Fri, May 11, 2007 at 04:07:18PM -0700, Arjan van de Ven wrote:
> > > > 
> > > > What's eating the battery life of my laptop? Why isn't it many more 
> > > > hours? Which software component causes the most power to be burned? 
> > > > These are important questions without a good answer... until now.
> > > 
> > > I get:
> > > 
> > > No detailed statistics available; please enable the CONFIG_TIMER_STATS
> > > kernel option
> > > 
> > 
> > Must run as root (rw to /proc/timer_stats is needed).
> 
> That file doesn't exist, despite CONFIG_TIMER_STATS being in
> /proc/config.gz.
> 

Then again, perhaps you have /proc/tstats instead.

If so apply this (well, you get the idea):

--- powertop/powertop.c 2007-05-12 05:01:15.000000000 +0100
+++ powertop_new/powertop.c     2007-05-12 05:08:46.000000000 +0100
@@ -212,8 +212,8 @@
 void stop_timerstats(void)
 {
        FILE *file;
-       file = fopen("/proc/timer_stats","w");
-       if (!file) {
+       if (!(file = fopen("/proc/timer_stats","w")) &&
+               !(file = fopen("/proc/stats","w")) ) {
                nostats = 1;
                return;
        }
@@ -223,8 +223,8 @@
 void start_timerstats(void)
 {
        FILE *file;
-       file = fopen("/proc/timer_stats","w");
-       if (!file) {
+       if (!(file = fopen("/proc/timer_stats","w")) &&
+               !(file = fopen("/proc/stats","w")) ) {
                nostats = 1;
                return;
        }
@@ -388,7 +388,7 @@
                i = 0;
                totalticks = 0;
                if (!nostats)
-                       file = popen("cat /proc/timer_stats | sort -n | tail -190", "r");
+                       file = popen("cat /proc/timer_stats 2>>/dev/null|| cat /proc/tstats | sort -n | tail -190", "r");
                while (file && !feof(file) && i<190) {
                        char *count, *pid, *process, *func;
                        int cnt;


-- 
Jose Celestino
----------------------------------------------------------------
http://www.msversus.org/     ; http://techp.org/petition/show/1
http://www.vinc17.org/noswpat.en.html
----------------------------------------------------------------
"And on the trillionth day, Man created Gods." -- Thomas D. Pate

Re: [announce] Intel announces the PowerTOP utility for Linux

[Jan Engelhardt]

On May 11 2007 16:07, Arjan van de Ven wrote:
>
> A typical Linux distribution has many components that wake the processor up
> frequently for no good reason. In our testing with PowerTOP, we have seen many
> cases where with some simple fixes, the battery life of typical laptops was
> increased by one hour or more!
>
> We are providing fixes for several of the issues we identified, and we
> encourage the Linux community to help us in this quest to get the maximum
> battery life out of your (hopefully Intel based) laptops. Try the PowerTOP
> tool, join the mailing list or the IRC channel and provide feedback, problem
> reports or fixes!

Yeah, hal happily wakes up every two seconds. So much for
the effectivity of NO_HZ.

# ps afx | grep hal
 ...
 3003 ?        S      0:00      \_ hald-addon-storage: polling /dev/hdb
 ...
# strace -p 3003
Process 3003 attached - interrupt to quit
restart_syscall(<... resuming interrupted call ...>) = 0
open("/dev/hdb", O_RDONLY|O_NONBLOCK|O_EXCL|O_LARGEFILE) = 4
ioctl(4, CDROM_DRIVE_STATUS, 0x7fffffff) = 1
close(4)                                = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({2, 0}, {2, 0})               = 0
open("/dev/hdb", O_RDONLY|O_NONBLOCK|O_EXCL|O_LARGEFILE) = 4
ioctl(4, CDROM_DRIVE_STATUS, 0x7fffffff) = 1
close(4)                                = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({2, 0}, {2, 0})               = 0
open("/dev/hdb", O_RDONLY|O_NONBLOCK|O_EXCL|O_LARGEFILE) = 4
ioctl(4, CDROM_DRIVE_STATUS, 0x7fffffff) = 1
close(4)                                = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({2, 0},  <unfinished ...>


	Jan
-- 

Re: [announce] Intel announces the PowerTOP utility for Linux

[Arjan van de Ven]

On Sat, 2007-05-12 at 13:00 +0200, Jan Engelhardt wrote:
> On May 11 2007 16:07, Arjan van de Ven wrote:
> >
> > A typical Linux distribution has many components that wake the processor up
> > frequently for no good reason. In our testing with PowerTOP, we have seen many
> > cases where with some simple fixes, the battery life of typical laptops was
> > increased by one hour or more!
> >
> > We are providing fixes for several of the issues we identified, and we
> > encourage the Linux community to help us in this quest to get the maximum
> > battery life out of your (hopefully Intel based) laptops. Try the PowerTOP
> > tool, join the mailing list or the IRC channel and provide feedback, problem
> > reports or fixes!
> 
> Yeah, hal happily wakes up every two seconds. So much for
> the effectivity of NO_HZ.


The AN patches that Kristen posted a few days ago will fix this part of
hal for real... assuming you have hardware with AN support that is.

they are in -mm now... should go mainline in like 2.6.23

Re: [announce] Intel announces the PowerTOP utility for Linux

[Alistair John Strachan]

On Saturday 12 May 2007 00:07:18 Arjan van de Ven wrote:
> What's eating the battery life of my laptop? Why isn't it many more
> hours? Which software component causes the most power to be burned?
> These are important questions without a good answer... until now.

This is a really great tool and presents a very intuitive alternative to the 
timer stats file..

On a Core 2 Duo Macbook, Linux always gets around 3.2h battery, OS X about 
4.2h. This tool has identified that uhci_hcd is where 75% of the ticks are 
going when X is not loaded. Unloading uhci_hcd drops the battery life back to 
around 4.2h, but I lose the keyboard.

Is there any way to find out what USB driver is causing usb_uhci to be this 
busy?

(BTW, the link to Keith's patch for dhcdbd seems to be broken on your 
homepage.)

-- 
Cheers,
Alistair.

Final year Computer Science undergraduate.
1F2 55 South Clerk Street, Edinburgh, UK.

Re: [announce] Intel announces the PowerTOP utility for Linux

[Jan Engelhardt]

On May 12 2007 22:12, Alistair John Strachan wrote:
>On Saturday 12 May 2007 00:07:18 Arjan van de Ven wrote:
>> What's eating the battery life of my laptop? Why isn't it many more
>> hours? Which software component causes the most power to be burned?
>> These are important questions without a good answer... until now.
>
>This is a really great tool and presents a very intuitive alternative to the 
>timer stats file..
>
>On a Core 2 Duo Macbook, Linux always gets around 3.2h battery, OS X about 
>4.2h. This tool has identified that uhci_hcd is where 75% of the ticks are 
>going when X is not loaded. Unloading uhci_hcd drops the battery life back to 
>around 4.2h, but I lose the keyboard.
>
>Is there any way to find out what USB driver is causing usb_uhci to be this 
>busy?

At its worst, it _is_ the USB chip that draws the power when it is active
(when uhci_hcd is loaded); does not need to be usbhid or so.


	Jan
-- 

Re: [announce] Intel announces the PowerTOP utility for Linux

[Alistair John Strachan]

On Monday 14 May 2007 21:22:50 Jan Engelhardt wrote:
> On May 12 2007 22:12, Alistair John Strachan wrote:
> >On Saturday 12 May 2007 00:07:18 Arjan van de Ven wrote:
> >> What's eating the battery life of my laptop? Why isn't it many more
> >> hours? Which software component causes the most power to be burned?
> >> These are important questions without a good answer... until now.
> >
> >This is a really great tool and presents a very intuitive alternative to
> > the timer stats file..
> >
> >On a Core 2 Duo Macbook, Linux always gets around 3.2h battery, OS X about
> >4.2h. This tool has identified that uhci_hcd is where 75% of the ticks are
> >going when X is not loaded. Unloading uhci_hcd drops the battery life back
> > to around 4.2h, but I lose the keyboard.
> >
> >Is there any way to find out what USB driver is causing usb_uhci to be
> > this busy?
>
> At its worst, it _is_ the USB chip that draws the power when it is active
> (when uhci_hcd is loaded); does not need to be usbhid or so.

This is certainly true, and to a significant extent it _was_ the uhci_hcd, but 
it turns out the main contributor to HZ here were the appletouch and hci_usb 
drivers. Disabling both drops the ticks down from about 850 to 150.

-- 
Cheers,
Alistair.

Final year Computer Science undergraduate.
1F2 55 South Clerk Street, Edinburgh, UK.