On 10/25/2010 4:03 AM, Thomas Renninger wrote:
On Monday 25 October 2010 12:04:28 Ingo Molnar wrote:
* Thomas Renninger<trenn@xxxxxxx> wrote:
New power trace events:
power:processor_idle
power:processor_frequency
power:machine_suspend
C-state/idle accounting events:
power:power_start
power:power_end
are replaced with:
power:processor_idle
Well, most power saving hw models (and the code implementing them) have this kind of
model:
enter power saving mode X
exit power saving mode
Where X is some sort of 'power saving deepness' attribute, right?
Sure.
But ACPI and afaik this model got picked up for PCI and other (sub-)archs
as well, defines state 0 as the non-power saving mode.
correct ,... "C0" is not power efficient... but it's still a valid OS
idle state!
Also tracking processor_idle_{start,end} as a separate event!
same for "S0"... S0 as standby state is still valid... sure it doesn't
save you much power... but that does not mean it's not valid.
(as indication, the Intel Moorestown platform, which is currently in
production and available to OEMs, has such a S0 standby state)
makes no sense and there is no need to introduce:
processor_idle_start/processor_idle_end
machine_suspend_start/machine_suspend_end
device_power_mode_start/device_power_mode_end
events.
Using state 0 as "exit/end", is much nicer for kernel/
userspace implementations/code and the user.
actually no; having written a few of these in userspace so far, having a
separate end event is easier to deal with;
the actions you take on entry and exit are complete separate code paths.
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