Method for optimizing wide port power management in a SAS topology

摘要

A SAS expander or initiator places PHYs in a wide port into a persistent reduced power state by signaling to the connected SAS device that the SAS expander or initiator intends to route data traffic through other PHYs in the wide port. The SAS expander or initiator and connected SAS device agree to disuse certain PHYs so that the PHYs enter a reduced power state according to SAS standards.

主权项

1. An SAS master apparatus comprising:
a processor; memory connected to the processor; a plurality of PHYs connected to the processor, each of the plurality of PHYs configured to be connected to one SAS slave; and computer executable program code configured to execute on the processor, wherein the computer executable program code is configured to: configure each of the plurality of PHYs into a single wide port; identify one or more PHYs in the plurality of PHYs eligible to enter a reduced power state; send a PHY deactivate signal utilizing out-of-band signaling to the one SAS slave indicating an intention of the SAS master to route data traffic through PHYs other than the one or more PHYs in the plurality of PHYs eligible to enter a reduced power state; receive a PHY deactivate response sent utilizing out-of-band signaling from the one SAS slave acknowledging the signal; and designate the one or more PHYs in the plurality of PHYs eligible to enter a reduced power state as unused by including the one or more PHYs in a data structure stored in memory, said data structure configured to record unused PHYs.