Intel E3-1220L v3 CM8064601467804 User Manual

Product codes

CM8064601467804

— For package C-states, the processor is not required to enter C0 state before

entering any other C-state.

— Entry into a package C-state may be subject to auto-demotion – that is, the

processor may keep the package in a deeper package C-state than requested

by the operating system if the processor determines, using heuristics, that the

deeper C-state results in better power/performance.

The processor exits a package C-state when a break event is detected. Depending on

the type of break event, the processor does the following:
•

If a core break event is received, the target core is activated and the break event

message is forwarded to the target core.
— If the break event is not masked, the target core enters the core C0 state and

the processor enters package C0 state.

— If the break event is masked, the processor attempts to re-enter its previous

package state.

•

If the break event was due to a memory access or snoop request,
— But the platform did not request to keep the processor in a higher package C-

state, the package returns to its previous C-state.

— And the platform requests a higher power C-state, the memory access or

snoop request is serviced and the package remains in the higher power C-

state.

The following table shows package C-state resolution for a dual-core processor. The

following figure summarizes package C-state transitions.

Table 17.

Coordination of Core Power States at the Package Level

Package C-State

Core 1

Core 0

Note: 1. If enabled, the package C-state will be C1E if all cores have resolved a core C1 state or higher.

Power Management—Processor

Intel

Xeon

Processor E3-1200 v3 Product Family

June 2013

Datasheet – Volume 1 of 2

Order No.: 328907-001