Hidden L0p Exit Latency In Read Workload
AssigneeSanDisk Technologies LLC
InventorShay BENISTY
Life of this patent
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Abstract
L0p exit latency can be decreased by sending a wake up signal so that the lane(s) of the link wake up just in time for data to be transmitted thereover. After parsing and scheduling a read command, the controller can determine the number of lanes needed to deliver the read data to the host device. If there are any lanes that need to be woken up from an electrically idle state, the wake up signal can be sent before the data is ready to transmit. The wake up signal is sent at a time equal to the L0p exit latency time provided by the host device. The time may be adjusted based upon measured L0p exit latency time. Additionally, the time can be coordinated with a timer in a L0p manager module or in coordination with events that occur when executing the read command.
Claims20
A data storage device, comprising:
- a memory device;
- and
- a controller coupled to the memory device, wherein the controller is configured to:
- record L0p exit latency of link partner, wherein the exit latency is a first period of time;
- initiate L0p request to save power;
- determine that data needs to be transferred to the link partner;
- initiate L0p exit request, wherein the initiation occurs at a second period of time, wherein the second period of time is before transferring the data to the link partner, and wherein the second period is equal to or greater than the first period of time;
- and
- transfer the data to the link partner.
A data storage device, comprising:
- a memory device;
- and
- a controller coupled to the memory device, wherein the controller is configured to:
- maintain a link between a host interface module (HIM) and a host device, wherein the link comprises a plurality of lanes and wherein the link has an exit latency;
- determine whether one or more lanes of the plurality of lanes needs to be woken up;
- send a L0p exit request to the host device, wherein the sending occurs at a first point in time;
- and
- transfer data to the host device, wherein the transferring occurs as a second point in time, and wherein a difference between the second point in time and the first point in time is equal to or greater than the exit latency.
A data storage device, comprising:
- means for storing data;
- and
- a controller coupled to the means for storing data, wherein the controller is configured to:
- parse and schedule a read command;
- compare L0p exit latency to values in a table containing time before seeing traffic on a link;
- determine a point in time for sending a L0p exit request to a host device, wherein the point in time is during execution of the read command and before data for the read command reaches a host interface module (HIM);
- send the L0p exit request to the host device;
- and
- send the data for the read command to the host device.
Dependencies are inferred from the claim text.