eiPower Saver Power Events explained

Some information on how eiPower tracks the power state of computer's and monitor's

The eiPower Saver Agent records a computer's and monitor's power state by generating a series of power events. There are 5 different power event types that the eiPower agent can generate with each type corresponds to a different power state combination of the computer and monitor. The meaning of these 5 event types are listed below. 

 

Power On (Id : 5)

This event means that both the computer and monitor(s) are powered On.

 

Power Off (Id : 4)

This event means that the computer is powered Off and the monitor is Off (or in Standby depending on the type of monitor)

 

Hibernate (Id : 3)

This event means that the computer is in Hibernate and the monitor is Off (or in Standby depending on the type of monitor)

 

Standby (Id :  2)

This event means that the computer is in Standby and the monitor is in Standby

 

Monitor (Id : 0)

This event means that the computer is powered ON and the monitor is in Standby.

Note : There is no Id : 1 event.

 

The following table shows a summary of the power states :
 

Event Type	Event Id	Computer State	Monitor State
Power On	5	On	On
Power Off	4	Off	Off (or Standby)
Hibernate	3	Hibernate	Off (or Standby)
Standby	2	Standby (Sleep)	Standby
Monitor	0	On	Standby

Only these 5 types are necessary as they cover all the meaningful power states of the computer/monitor. Other states not in this list are not possible (or are transient) and hence have no event type. For example, it is not necessary to have an event to represent when the computer is Off and the monitor is On, because when the computer turns off any attached monitors will automatically go into a low power state.

The eiPower agent generates a power event each time there is a change to the power state, Offsite state (if enabled) or Battery state of the computer or monitor. The new power event represents the new power state of the computer/monitor.

Each power event sent from the eiPower agent has the following attributes :

 

Attribute Name	Description
_ResourceGuid	Guid of the computer sending the event
Type	Id of one of the event types described above
Start	Date/time when this power event started
Time	Date/time when the power event ended
Duration	Duration in seconds of this power event (this just the difference between the Start and End dates measured in seconds.
Offsite	If Offsite detection is enabled this indicates whether or not the computer was Offsite at this time
Running On Battery	Indicates whether or not the computer was running on battery at this time

eiPower Saver events are stored in the Evt_ei_PowerEvents table.

The agent stores the list of power events locally and then send them to the SMP server at least once every 24 hours.

In normal operation the eiPower agent will generate a continuous set of power events without any gaps or overlaps. That is, the agent will send power events where the Start date (Start attribute) of each event will be equal to the End date (Time attribute) of the previous power event. This ensures that we know the power state of the computer and monitor at all times and can perform our energy usage, cost and CO2 emissions accurately. 

When there are power events where the event's end date is not equal to the start date of the previous event we say that we have a gap in the data or unknown period. These gaps will occur if the eiPower agent service is shutdown or if there is a problem on the server (such as a licensing error) and the event data is not being loaded into the CMDB. Gaps will not occur when the computer is allowed to shutdown normal, however they may occur if the computer shuts down unexpectedly.

Computer Power Events log

To view the Power events generated by a computer you can right click on the computer and select eiPower Saver > Power Events Report. This report shows the list of power events generated by the selected computer over a specified time period.

The Power Events Report will look like the following :

From this report you can see the changes in the power state of the computer and monitor over time. From looking at a single event it is only possible to determine what the computer's and monitor's power state is between the event's start and end times. In order to see the changes in the computer's and monitor's power states it is necessary to compare each event with its previous event.

From the events show above we can deduce the following power state transitions have occurred :

1. Computer and monitor are both initially Off 
2. Computer and monitor are turned On
3. Computer and monitor remain On.
   Note; not all events represent a transition in state - in some situations events are generated when no power state transition has occurred - this is normal.
4. Computer and Monitor went into Standby
5. Computer woke up but Monitor remained in Standby.
   This condition typically occurs when the computer wakes due to a schedule wakeup - rather than a user waking the computer up.
6. Monitor wakes up 
7. Computer and Monitor go into standby