SAS latency based routing
AssigneeHewlett-Packard Development Company, L.P.
InventorsMichael G Myrah, Balaji Natrajan, Rodrigo Stoll Martins Machado
Life of this patent
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Abstract
Techniques for operating a serial attached SCSI (SAS) expander that includes a latency table comprising entries of outbound PHYS with latency values associated with connections between inbound PHYs and outbound PHYs. A storage management module to, in response to receipt of a command from an initiator device associated with an inbound PHY to route data to a target device associated with an outbound PHY, select from the latency table a random outbound PHY from among a plurality of outbound PHYs, wherein the random selection is based on weighted average of latency values of the outbound PHY entries of the latency table.
Claims17
A serial attached SCSI (SAS) expander comprising:
- a latency table comprising entries of outbound PHYs with latency values associated with connections between inbound PHYs associated with initiator devices and the outbound PHYs associated with target devices;
- and
- a storage management module to:
- in response to receipt of a command from an initiator device associated with an inbound PHY to route data to a target device associated with an outbound PHY, select from the latency table a random outbound PHY from among the outbound PHYs, wherein the random selection is based on weighted average values of the latency values of the entries of the outbound PHYs of the latency table, wherein the latency values are calculated based on a difference in time between when a Close primitive is sent to the target device and an Open Accept primitive is received from the target device.
A method of operating a serial attached SCSI (SAS) expander comprising:
- configuring a latency table comprising entries of outbound PHYs with latency values associated with connections between inbound PHYs and the outbound PHYs;
- and
- in response to receipt of a command from an initiator device associated with an inbound PHY to route data to a target device associated with an outbound PHY, selecting from the latency table a random outbound PHY from among the outbound PHYs, wherein the random selection is based on weighted average of the latency values of the entries of the outbound PHYs of the latency table, wherein the latency values are calculated based on a difference in time between when a Close primitive is sent to the target device and an Open Accept primitive is received from the target device.
A non-transitory computer computer-readable medium having computer executable instructions stored thereon to operate a serial attached SCSI (SAS) expander, the instructions are executable by a processor to:
- configure a latency table comprising entries of outbound PHYs with latency values associated with connections between inbound PHYs and the outbound PHYs;
- and
- in response to receipt of a command from an initiator device associated with an inbound PHY to route data to a target device associated with an outbound PHY, select from the latency table a random outbound PHY from among the outbound PHYs, wherein the random selection is based on weighted average values of the latency values of the entries of the outbound PHYs of the latency table, wherein the latency values are calculated based on a difference in time between when a Close primitive is sent to the target device and an Open Accept primitive is received from the target device.
Dependencies are inferred from the claim text.