9:57 p.m.
Hi,
On my ThinkPad T440s, PowerTOP-2.5 shows that the e1000e kernel module
is drawing considerable amount of power when not it use (cable unplugged):
The battery reports a discharge rate of 5.86 W
The estimated remaining time is 5 hours, 11 minutes
Summary: 143.9 wakeups/second, 10.9 GPU ops/seconds, 0.0 VFS ops/sec and 2.7% CPU use
Power est. Usage Events/s Category Description
3.76 W 49.0% Device Display backlight
1.46 W 0.0 pkts/s Device Network interface: eth0 (e1000e)
What I observed is that, if I remove the e1000e kernel module with
`rmmod e1000e`, the corresponding entry in PowerTOP is gone, but the
battery discharge rate stays the same. So, I am guessing there is
either a hardware short-circuit somewhere on the motherboard or a bug in
the underlying power management software or an estimation error. Any
hints on how I can confirm/debug this?
Thanks,
Sree
2:02 a.m.
New subject: [Powertop] Idle power consumption of Intel e1000e kernel module
Hi,
On Sat, Dec 21, 2013 at 12:00:01PM -0800, powertop-request(a)lists.01.org wrote:
From: Sree Harsha Totakura <sreeharsha(a)totakura.in>
Hi,
On my ThinkPad T440s, PowerTOP-2.5 shows that the e1000e kernel module
is drawing considerable amount of power when not it use (cable unplugged):
> The battery reports a discharge rate of 5.86 W
> The estimated remaining time is 5 hours, 11 minutes
>
> Summary: 143.9 wakeups/second, 10.9 GPU ops/seconds, 0.0 VFS ops/sec and 2.7% CPU
use
>
> Power est. Usage Events/s Category Description
> 3.76 W 49.0% Device Display backlight
> 1.46 W 0.0 pkts/s Device Network interface: eth0
(e1000e)
What I observed is that, if I remove the e1000e kernel module with
`rmmod e1000e`, the corresponding entry in PowerTOP is gone, but the
battery discharge rate stays the same. So, I am guessing there is
either a hardware short-circuit somewhere on the motherboard or a bug in
the underlying power management software or an estimation error. Any
hints on how I can confirm/debug this?
Well, it could simply be that it *is* that hardware which does cause the
consumption, but that e1000e does not activate the fullest possible mode
of power management upon unload of the device driver.
What usually consumes a lot of power with network devices is the PHY
area, AFAIK, so it could be that e1000e simply leaves PHY in a less than
optimal state upon unload, thus drawing several (half-)watts too many.
- check which suitable power management parameters the module provides
(modinfo e1000e)
- try to experiment with that to gain some experience
- check e1000e source to see what it does on unload, and what it does wrong ;)
And if you suspect a problem with improper power management settings on
driver unload, then either fix it or file a bug on kernel.org Bugzilla :)
HTH,
Andreas Mohr
3192
days inactive
3193
days old
1 comments
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participants (2)
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Andreas Mohr -
Sree Harsha Totakura