Update sysfs interface documentation to include energy meters and power
meter averaging intervals.
Signed-off-by: Darrick J. Wong <[email protected]>
---
Documentation/hwmon/sysfs-interface | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
index f4a8ebc..85e6654 100644
--- a/Documentation/hwmon/sysfs-interface
+++ b/Documentation/hwmon/sysfs-interface
@@ -328,6 +328,14 @@ curr[1-*]_input Current input value
Unit: milliampere
RO
+**********
+* Energy *
+**********
+
+energy[1-*]_input Instantaneous energy use
+ Unit: microJoule
+ RO
+
*********
* Power *
*********
@@ -336,6 +344,10 @@ power[1-*]_average Average power use
Unit: microWatt
RO
+power[1-*]_interval Power use averaging interval
+ Unit: milliseconds
+ RW
+
power[1-*]_average_highest Historical average maximum power use
Unit: microWatt
RO
Hi Darrick,
On Fri, 28 Mar 2008 14:36:46 -0700, Darrick J. Wong wrote:
> Update sysfs interface documentation to include energy meters and power
> meter averaging intervals.
>
> Signed-off-by: Darrick J. Wong <[email protected]>
> ---
>
> Documentation/hwmon/sysfs-interface | 12 ++++++++++++
> 1 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
> index f4a8ebc..85e6654 100644
> --- a/Documentation/hwmon/sysfs-interface
> +++ b/Documentation/hwmon/sysfs-interface
> @@ -328,6 +328,14 @@ curr[1-*]_input Current input value
> Unit: milliampere
> RO
>
> +**********
> +* Energy *
> +**********
> +
> +energy[1-*]_input Instantaneous energy use
This doesn't make sense to me. Energy is a quantity, it exists
independently of time. An "instantaneous energy use" only makes sense
if you tell in what (presumably very small) amount of time the energy
was used... and then what you are measuring is not an energy but a
power, for which we already have an interface. Please clarify.
> + Unit: microJoule
> + RO
> +
> *********
> * Power *
> *********
> @@ -336,6 +344,10 @@ power[1-*]_average Average power use
> Unit: microWatt
> RO
>
> +power[1-*]_interval Power use averaging interval
Wouldn't power[1-*]_average_interval be clearer?
> + Unit: milliseconds
Nitpicking for consistency: millisecond (no trailing s).
What values do you expect for this entry? I am wondering if it's safe
to use millisecond as a unit. Is it unlikely that a future chip will
support averaging intervals below the millisecond?
> + RW
> +
> power[1-*]_average_highest Historical average maximum power use
> Unit: microWatt
> RO
--
Jean Delvare
Jean Delvare wrote:
> On Fri, 28 Mar 2008 14:36:46 -0700, Darrick J. Wong wrote:
>> +energy[1-*]_input Instantaneous energy use
>
> This doesn't make sense to me. Energy is a quantity, it exists
> independently of time. An "instantaneous energy use" only makes sense
> if you tell in what (presumably very small) amount of time the energy
> was used... and then what you are measuring is not an energy but a
> power, for which we already have an interface. Please clarify.
I agree. May I suggest "cumulative energy use"?
Wes Felter - [email protected]
On Sat, Mar 29, 2008 at 02:56:03PM +0100, Jean Delvare wrote:
> > +energy[1-*]_input Instantaneous energy use
>
> This doesn't make sense to me. Energy is a quantity, it exists
> independently of time. An "instantaneous energy use" only makes sense
> if you tell in what (presumably very small) amount of time the energy
> was used... and then what you are measuring is not an energy but a
> power, for which we already have an interface. Please clarify.
Wes Felter suggested "Cumulative energy use", and I'll go with that.
> > +power[1-*]_interval Power use averaging interval
>
> Wouldn't power[1-*]_average_interval be clearer?
Given that power is energy used over a period of time, I wonder if it
might be more accurate to remove powerX_input and leave this name alone.
That said, it does seem to be the case that interval names take the
format "${sensorfile}_interval", so I suppose it makes more sense the
way that you suggest.
> > + Unit: milliseconds
>
> Nitpicking for consistency: millisecond (no trailing s).
>
> What values do you expect for this entry? I am wondering if it's safe
> to use millisecond as a unit. Is it unlikely that a future chip will
> support averaging intervals below the millisecond?
It's possible that a future chip could do this, though today we only
support intervals in the hundreds of milliseconds. The default for the
ibmaem driver is currently 1s.
--D