On 05/19/09 06:23 PM, Edward Pilatowicz wrote:
> On Tue, May 19, 2009 at 10:37:45AM -0700, Terry Whatley wrote:
>
>> 4.3.4 disk power attribute driver properties
>>
>> sd(7D) will export a set of driver properties to indicate a disk's
>> power attributes. See Table-2.
>>
>> Table-1 Disk Power Attribute Properties (array properties are indexed
>> by power state in order of ascending power levels)
>> ------------------------------------------------------------------------
>> Prop Name Prop Type | Prop Description
>> ------------------------------------------------------------------------
>> "pm-resource-type" String | "resource-spindle-disk" for the
>> | spindle disks
>> ------------------------------------------------------------------------
>> "pm-perf" Integer array | array of average R/W
>> | performance percentages
>> ------------------------------------------------------------------------
>> "pm-pwr-saving" Integer array | array of average power saving in
>> | units of 0.1watt
>> ------------------------------------------------------------------------
>> "pm-latency" Integer array | array of time to first data in units
>> | of 100ms
>> ------------------------------------------------------------------------
>>
>>
>
> exporting performance statistics via device properties seems weird to
> me. is there a precedent for this? why isn't this information being
> exported via kstats? do we really want to train users to start using
> prtconf -v to get performance data?
>
> ed
>
I think these are not performance statistics. I believe that these are
static arrays that are specific for a device type (most likely Sun disks
only), that correlate specific power level with performance and power
savings. These properties, I believe, are to be used by a storage power
manager to decide at what power level disk should run at given time.
Jane Chu may correct me here...
-Pawel
