linux-kernel - Re: [RFC][PATCH 12/12] PM / r8169: Add simplified run-time PM support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 3 Jan 2010 22:01:14 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Pavel Machek <pavel@....cz>
Cc:	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Oliver Neukum <oliver@...kum.org>,
	Shaohua Li <shaohua.li@...el.com>,
	Bjorn Helgaas <bjorn.helgaas@...com>,
	Francois Romieu <romieu@...zoreil.com>,
	Len Brown <lenb@...nel.org>
Subject: Re: [RFC][PATCH 12/12] PM / r8169: Add simplified run-time PM support

On Sunday 03 January 2010, Pavel Machek wrote:
> 
> > > On notebooks, you can often use
> > > 
> > > pavel@amd:/data/l/linux-msm/arch/arm/mach-msm$ cat
> > > /proc/acpi/battery/BAT0/state 
> > > present:                 yes
> > > capacity state:          ok
> > > charging state:          charged
> > > present rate:            0 mW
> > > remaining capacity:      71830 mWh
> > > present voltage:         16277 mV
> > > 
> > > ...present rate is often usable-enough.
> > 
> > Using /proc/acpi/battery/BAT1/state I measured the energy drawn in 10 minutes
> > both with the network adapter in D0 and D3hot.  The results were that with the
> > network adapter in D0 the box drew 2476 mWh, while with the network adapter in
> > D3hot it drew 2361 mWh.  The difference is 115 mWh, or about 5% on this
> > particular box.
> > 
> > This means about 0.1 Wh in 10 minutes, so we can save about 0.6 Wh per hour.
> 
> Which means it saves 0.6W :-). Measuring power in Wh/h is "interesting".

You can't save power, you can only save energy.  Wh is just an energy unit.

> Ok, that's consistent with my experiments, ethernet transciever was around 1W... Thanks.

No big deal.

Rafael
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/