Re: [linux-pm] [PATCH] pm: Add runtime PM statistics to sysfs

From: Alan Stern
Date: Fri Jul 09 2010 - 11:00:45 EST


On Thu, 8 Jul 2010, Arjan van de Ven wrote:

> From: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
> Subject: pm: Add runtime PM statistics to sysfs
>
> In order for PowerTOP to be able to report how well the new runtime PM is working
> for the various drivers, the kernel needs to export some basic statistics in sysfs.
>
> This patch adds two sysfs files in the runtime PM domain that expose the
> total time a device has been active, and the time a device has been suspended.
>
> With this PowerTOP can compute the activity percentage
>
> Active %age = 100 * (delta active) / (delta active + delta suspended)
>
> and present the information to the user.
>
> I've written the PowerTOP code (slated for version 1.12) already, and the output looks
> like this:
>
> Runtime Device Power Management statistics
> Active Device name
> 10.0% 06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E


> @@ -411,6 +433,7 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
> }
>
> if (retval) {
> + update_pm_runtime_accounting(dev);
> dev->power.runtime_status = RPM_SUSPENDED;
> pm_runtime_cancel_pending(dev);
> } else {

This line was added in the wrong place. It belongs either before the
"if (retval) {" or after the "} else {".

Alan Stern

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