Reducing memory power usage in far memory
Some embodiments include apparatuses and electrical models associated with the apparatus. One of the apparatuses includes a power control unit to monitor a power state of the apparatus for entry into a standby mode. The apparatus can include a two-level memory (2LM) hardware accelerator to, responsive to a notification from the power control unit of entry into the standby mode, flush dynamic random access memory (DRAM) content from a first memory part to a second memory part. The apparatus can include processing circuitry to determine memory utilization and move memory from a first memory portion to a second memory portion responsive to memory utilization exceeding a threshold. Other methods systems and apparatuses are described.
1 . An apparatus comprising:
a power control circuit to monitor a power state of the apparatus for entry into a standby mode; and
a two-level memory (2LM) hardware accelerator configured to, responsive to a notification from the power control unit of entry into the standby mode, move at least a portion of pinned and locked page content from a first CXL memory part to a second non CXL memory part responsive to a determination that a memory utilization for the first CXL memory part meets a first memory utilization threshold.
2 . The apparatus of claim 1 , wherein the first memory part includes near memory and the second memory part includes far memory.
3 . The apparatus of claim 2 , wherein responsive to a notification from the power control circuit of exit from the standby mode, the 2LM hardware accelerator is further configured to move DRAM content from the second memory part to the first memory part.
4 . The apparatus of claim 3 , wherein responsive to exiting from the standby mode, the power control circuit is further configured to restore system context.
5 . The apparatus of claim 3 , wherein responsive to exiting from the standby mode, the power control circuit is further configured to provide a signal commanding the DRAM to exit from self-refresh and to perform a memory unblock operation.
6 . The apparatus of claim 1 , wherein the standby mode comprises a Modern Standby (MOS) state.
7 . The apparatus of claim 6 , wherein the standby mode comprises a MoS S0i4 state.
8 . The apparatus of claim 1 , wherein the apparatus further comprises a power management controller, and wherein the power control circuit is further configured to notify the power management controller that power is to be removed from the apparatus, subsequent to the flushing.
9 . A non-transitory computer readable storage medium having a plurality of instructions stored thereon, which, when executed by a processor, cause the processor to perform operations comprising:
receiving, from a power control circuit, notifications regarding power state of an apparatus associated with the processor; and
responsive to a notification of entry into a standby mode, flushing pinned and locked page content from a first CXL memory part to a second DRAM memory part.
10 . The non-transitory computer readable storage medium of claim 9 , wherein the first memory part includes near memory and the second memory part includes far memory, and wherein the processor is configured to, responsive to a notification of exit from the standby mode, move CXL content from the second memory part to the first memory part.
11 . The non-transitory computer readable storage medium of claim 10 , wherein responsive to exiting from the standby mode, the processor is further configured to restore system context.
12 . The non-transitory computer readable storage medium of claim 9 , wherein the standby mode comprises a Modern Standby (MOS) S0i4 state.
13 . An apparatus comprising:
a power control circuit to monitor power state of the apparatus; and
processing circuitry coupled to the power control circuit and to a memory, wherein, upon trigger of a standby entry, the power control circuit triggers the processing circuitry to:
determine memory utilization and pinned and locked page information in a first memory portion, and
move at least a portion of the pinned and locked page information to a second memory portion if a first threshold memory utilization has been reached, wherein the first memory portion includes CXL memory, and the second memory portion includes non-volatile memory or dynamic random access memory (DRAM).
14 . The apparatus of claim 13 , wherein the CXL memory enters a low-power state subsequent to moving the pinned and locked page information.
15 . The apparatus of claim 13 , wherein the power control circuit is communicatively coupled to an operating system, wherein the operating system is to turn off bus mastering after the memory controller moves at least the portion of the pinned and locked page information, upon trigger of the standby entry, from the first memory portion to the second memory portion.
16 . The apparatus of claim 13 , wherein if direct memory access is off, the power control circuit checks whether a time to next timer event is greater than a threshold prior to moving at least the portion of the pinned and locked page information.
17 . A non-transitory computer readable storage medium having a plurality of instructions stored thereon, which, when executed by a processor, cause the processor to perform operations comprising:
receiving, from a power control circuit, notifications regarding power state of an apparatus associated with the processor; and
responsive to a notification of entry into a standby mode, determining memory utilization and pinned and locked page information in a first memory portion, and
moving at least a portion of the pinned and locked page information to a second memory portion if a first threshold memory utilization has been reached, wherein the first memory portion comprises Compute Express Link (CXL) memory and the second memory portion comprises dynamic random access memory (DRAM).
18 . The non-transitory computer readable storage medium of claim 17 , wherein the CXL memory enters a low-power state subsequent to moving the pinned and locked page information.
19 . The non-transitory computer readable storage medium of claim 17 , wherein the processor is further configured to perform operations including turning off bus mastering after moving at least the portion of the pinned and locked page information, upon trigger of the standby entry, from the first memory portion to the second memory portion.
20 . The non-transitory computer readable storage medium of claim 17 , wherein if direct memory access is off, the power control circuit checks whether a time to next timer event is greater than a threshold prior to moving at least the portion of the pinned and locked page information.