US9270756B2 - Enhancing active link utilization in serial attached SCSI topologies - Google Patents
Enhancing active link utilization in serial attached SCSI topologies Download PDFInfo
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- US9270756B2 US9270756B2 US14/182,008 US201414182008A US9270756B2 US 9270756 B2 US9270756 B2 US 9270756B2 US 201414182008 A US201414182008 A US 201414182008A US 9270756 B2 US9270756 B2 US 9270756B2
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/01—Protocols
- H04L67/10—Protocols in which an application is distributed across nodes in the network
- H04L67/1097—Protocols in which an application is distributed across nodes in the network for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F13/38—Information transfer, e.g. on bus
- G06F13/382—Information transfer, e.g. on bus using universal interface adapter
- G06F13/385—Information transfer, e.g. on bus using universal interface adapter for adaptation of a particular data processing system to different peripheral devices
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0602—Interfaces specially adapted for storage systems specifically adapted to achieve a particular effect
- G06F3/061—Improving I/O performance
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0629—Configuration or reconfiguration of storage systems
- G06F3/0635—Configuration or reconfiguration of storage systems by changing the path, e.g. traffic rerouting, path reconfiguration
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0653—Monitoring storage devices or systems
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0668—Interfaces specially adapted for storage systems adopting a particular infrastructure
- G06F3/067—Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2213/00—Indexing scheme relating to interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F2213/0028—Serial attached SCSI [SAS]
Definitions
- aspects of the present application relate to networking. More specifically, certain implementations of the present disclosure relate to enhancing active link utilization in serial attached SCSI (SAS) topologies.
- SAS serial attached SCSI
- a network device that is configured to provide an expander function within a serial attached SCSI (SAS) topology may monitor link utilization within the SAS topology, wherein the monitoring may comprise determining availability of links in other nodes in the SAS topology; and managing connection requests received by the expander function based on the monitoring of link utilization, wherein the managing comprises determining for each received connection request when link unavailability in the other nodes within the SAS topology prevents connectivity to a destination node corresponding to the connection request.
- SAS serial attached SCSI
- FIG. 1 illustrates an example network incorporating a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIG. 2A illustrates an example link utilization scenario in a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIG. 2B illustrates an example use of a link utilization enhancement scheme in a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIGS. 3A and 3B illustrate an example use of a link utilization enhancement scheme in a Serial Attached SCSI (SAS) based networking topology, based on sharing of link related data.
- SAS Serial Attached SCSI
- FIG. 4 is a flowchart illustrating an example process for handling connection requests in a SAS topology incorporating use of enhanced link utilization.
- circuits and circuitry refer to physical electronic components (i.e. hardware) and any software and/or firmware (“code”) which may configure the hardware, be executed by the hardware, and or otherwise be associated with the hardware.
- code software and/or firmware
- a particular processor and memory may comprise a first “circuit” when executing a first plurality of lines of code and may comprise a second “circuit” when executing a second plurality of lines of code.
- and/or means any one or more of the items in the list joined by “and/or”.
- x and/or y means any element of the three-element set ⁇ (x), (y), (x, y) ⁇ .
- x, y, and/or z means any element of the seven-element set ⁇ (x), (y), (z), (x, y), (x, z), (y, z), (x, y, z) ⁇ .
- block and “module” refer to functions than can be performed by one or more circuits.
- example means serving as a non-limiting example, instance, or illustration.
- the terms “for example” and “e.g.,” introduce a list of one or more non-limiting examples, instances, or illustrations.
- circuitry is “operable” to perform a function whenever the circuitry comprises the necessary hardware and code (if any is necessary) to perform the function, regardless of whether performance of the function is disabled, or not enabled, by some user-configurable setting.
- FIG. 1 illustrates an example network incorporating a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIG. 1 there is shown a plurality of network devices 110 1 and 110 2 and 120 A - 120 D .
- Each of the network devices may comprise suitable circuitry for implementing various aspects of the present disclosure.
- a network device may comprise suitable circuitry configured for performing or supporting various functions, operations, applications, and/or services.
- the functions, operations, applications, and/or services performed or supported by the network device may be run or controlled based on user instructions and/or pre-configured instructions.
- the network device may support communication of data, such as via wired and/or wireless connections, in accordance with one or more supported wireless and/or wired protocols or standards.
- Examples of network devices may comprise computers (e.g., servers, desktops, and laptops) and the like. The disclosure, however, is not limited to any particular type of network device.
- the plurality of network devices 110 1 and 110 2 and 120 A - 120 D may be part of a topology 100 .
- the topology 100 may comprise a plurality of systems, devices, and/or components, for supporting interactions in accordance with various types of connections, interfaces, and/or protocols.
- the topology 100 may be configured to support Serial Attached SCSI (SAS) based interactions (as such it may be referred hereinafter as SAS topology).
- SAS Serial Attached SCSI
- the network devices 110 1 and 110 2 and 120 A - 120 D may be configured provide different functions, such as in accordance with a particular topology implemented using the devices.
- the network devices 110 1 and 110 2 may be utilized as ‘servers’ (and as such they may be referred hereinafter as the servers 110 1 and 110 2 ); whereas the network devices 110 1 and 110 2 and 120 A - 120 D the may be utilized as ‘clients’ (and as such they may be referred hereinafter as the clients 120 A - 120 D ).
- the servers 110 1 and 110 2 may be utilized to run SAS controller functions (e.g., SAS controllers 112 1 and 112 2 , respectively), whereas the clients 120 A - 120 D may be used to run SAS expander functions (e.g., SAS expanders 122 A - 122 D , respectively), which may be utilized in providing connectivity within the SAS topology 100 .
- SAS controller functions e.g., SAS controllers 112 1 and 112 2 , respectively
- SAS expander functions e.g., SAS expanders 122 A - 122 D , respectively
- SAS topologies may also comprise such (other) components as SAS devices (SDs) (e.g., devices providing storage resources), and network links for providing connectivity between the network nodes (e.g., devices in which expanders and controllers are run).
- SDs SAS devices
- the SAS topology 100 may also comprise SAS devices (SDs) A 1 -A 4 , B 1 -B 2 , C 1 -C 4 , and D 1 -D 4 , which may be attached to SAS expanders 122 A - 122 D , respectively.
- the topology SAS may also comprise various links between its constituent components—e.g., links L 1,1 and L 1,2 between expander 122 A and controllers 112 1 and 112 2 , respectively; links L 2 between expanders 122 A and 122 B ; and links L 3,1 and L 3,2 between expander 122 A and expanders 122 C and 122 D , respectively.
- links L 1,1 and L 1,2 between expander 122 A and controllers 112 1 and 112 2 , respectively
- links L 2 between expanders 122 A and 122 B
- links L 3,1 and L 3,2 between expander 122 A and expanders 122 C and 122 D respectively.
- the structure of the SAS topology 100 as shown in FIG. 1 is merely an illustrative, non-limiting example, and various implementations in accordance with the present disclosure are not limited to that particular structure and would apply in a similar manner to any SAS topology.
- SAS expanders may be used to provide system connectivity and service delivery within SAS topology—e.g., facilitating connectivity to SDs attached to the SAS expanders (e.g., drives or other storage resources in the corresponding network devices), to other expanders, and to the SAS controllers.
- partial paths may be setup in SAS topologies.
- a connection request (e.g., in the form of open access frame or ‘OAF’) may be sent, such as from a SAS device (SD), and may be forwarded by the expanders—i.e., from one expander to another, until it reaches a designated destination (e.g., a SAS controller).
- a designated destination e.g., a SAS controller
- corresponding links between the expanders in the path towards the destination may be used and reserved for that connection request.
- an OAF may stop before reaching the destination. For example, when an OAF that is being forwarded reaches a node that lacks available links to the next node in the chain, the OAF may need to wait and arbitrate for the next level of path to become available.
- connection request (OAF)
- the node e.g., expander
- AIP arbitration-in-progress
- the partial path acquired for handling the pending OAF request would remain idle (i.e., the links used to set it up all the way to the last expander remain in use), and may remain idle until the arbitration is resolved successfully—e.g., a link to next level, in the expander in which the arbitration is being done, becomes available (e.g., one of the links that were being used is freed, such as when another connection is terminated), or until some event occurs resulting in cessation of connection attempt—e.g., the arbitration is terminated (such as based on timer expiry) before acquiring link to the next node, or if a connection request with higher priority is received by any of the node in the partial path, resulting in dropping of the established partial path (or portions thereof) to free some links.
- the arbitration is terminated (such as based on timer expiry) before acquiring link to the next node, or if a connection request with higher priority is received by any of the node in the partial path, resulting in dropping of the established partial path (or
- the partial path acquired by the OAF may comprise some shared path portions, which may be used for completion of equal or low priority connection requests and subsequent flow of input/output (TO) traffic from other end devices. Nonetheless, with existing systems, such low/equal priority connection requests have to wait on partial paths of these higher priority OAFs. Therefore, partial paths may cause undesirable inefficiencies in SAS topologies, particularly where they result in use of links that are unnecessarily taken simply to setup up a path all the way from the start point (the initiator) to the last node in the partial path (e.g., the last expander, in which arbitration is performed).
- SAS topologies may be enhanced, such as by localizing partial paths in a manner that may enable reducing idle partial path links in the SAS topology, thereby increasing the active link utilization for overall improvement in IO throughput of the SAS topology.
- localization of partial paths may help in significantly reducing the congestion at the upstream links and those links can be efficiently used for increasing the throughput of overall IO traffic in that topology.
- an enhanced link utilization scheme may be utilized in a SAS scheme. For example, when a SAS expander receives an OAF, it may determine if there are any pending connection requests through that SAS expander. If so, the SAS expander may compare the received OAF with the pending connection requests. For example, the SAS expander may compare the destination SAS address in the received OAF with destination SAS addressees of all currently pending connection requests. If there is at least one pending connection with higher priority request in which the destination SAS address matches with the destination SAS address in the received OAF, and the SAS expander is currently receiving AIP responses for that pending connection request, the SAS expander would not forward the received OAF through to one of the available destinations.
- the SAS expander may generate and forward (send back) the AIP responses (on the incoming link of the received OAF), and may continue to do so for as long as the condition—i.e., reception of AIP responses for the matched pending connection request(s)—persists. This may be done because if the SAS expander is already receiving AIP responses for higher priority requests (for a destination SAS address), then any other new OAF requests for the same destination SAS address need not acquire and block the further available partial paths, and those partial paths should be made available for completing/forwarding other possible connection requests and IO traffic.
- Use of enhanced link utilization in SAS topologies is described in more detail in connection with the following figures.
- FIG. 2A illustrates an example link utilization scenario in a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIG. 2A there is shown topology 100 of FIG. 1 .
- the controllers 112 1 and 112 2 , the expanders 122 A - 122 D , and the SAS devices A 1 -A 4 , B 1 -B 2 , C 1 -C 4 , and D 1 -D 4 ) are shown in FIG. 2A .
- FIG. 2A An example link utilization scenario, based on legacy approaches, is shown in FIG. 2A .
- FIG. 2A is a link utilization scenario in which a request may be denied due to inefficient managing of link utilization in the overall topology.
- the expander 122 A which may have 4 links with each of the controllers 112 1 and 112 2 , may utilize the four links to controller 112 1 .
- a connection 210 may be established through the expander 122 A between the SD A 1 and the controller 112 1 ; a second connection 220 may be established through the expander 122 A between the SD A 2 and the controller 112 1 ; a third connection 230 may be established through the expander 122 B then expander 122 A , between the SD B 1 and the controller 112 1 ; and fourth connection 240 may be established through the expander 122 B then expander 122 A , between the SD B 2 and the controller 112 1 , resulting in active connections being established over all available controller links between the expander 122 A and the controller 112 1 .
- an attempt to establish connection 250 from the SD C 1 to the controller 112 1 may result in acquiring a path all the way to the expender 122 A —i.e., resulting in utilization of links (for establishing connections) between the expander 122 C and expander 122 B , and between the expander 122 B and expander 122 A , as shown in FIG. 2A .
- the expander 122 A may determine that there is no available links to the controller 110 1 , sending the SD C 1 arbitration-in-progress (AIP) responses to connection requests received therefrom.
- AIP arbitration-in-progress
- Such link utilization may prohibit further establishment of connections (particularly ones corresponding to connection requests with equal or lower priority) traversing the expander 122 B and expander 122 A , including connections that may otherwise be possible beyond expender 122 A .
- a connection request to establish connection 270 , and subsequent input/output (TO) traffic, between the SD D 4 and the controller 112 2 would be blocked within the expender 122 B because all links between it and the expander 122 A are used up (including the two links therebetween, which may be utilized for partial paths from the SDs C 1 and C 4 , which may correspond to connection requests having higher or equal priority), despite the availability of (all the) links between the expander 122 A and the controller 112 2 .
- An enhanced link utilization scheme may mitigate prevention of connectivity by freeing links that are unnecessarily utilized for partial paths (i.e., links that are used in paths established for connections that fail to reach the intended target within the topology), such as by ensuring that these partial paths are terminated or blocked much sooner within the topology.
- An example of such enhanced link utilization corresponding to the scenario in the present figure is described in more detail in connection with FIG. 2B .
- FIG. 2B illustrates an example use of a link utilization enhancement scheme in a Serial Attached SCSI (SAS) based networking topology.
- SAS Serial Attached SCSI
- FIG. 2B An example of enhanced link utilization, in accordance with the present disclosure, is shown in FIG. 2B .
- the example enhanced link utilization shown in FIG. 2B may correspond to the connection scenario of FIG. 2A .
- all of the (4) links between expander 122 A and the controller 112 1 may be utilized—e.g., in establishing connections 210 , 220 , 230 , and 240 , between the controller 112 1 and each of SDs A 1 , A 2 , B 1 , and B 2 , respectively.
- all available (4) links between the expander 122 A and the controller 112 1 are utilized, no further connections into the controller 112 1 through the expander 122 A may be possible.
- the expanders may be configured to develop awareness of link availability (or unavailability) within the topology, including knowledge of link of unavailability in nodes upstream from the expanders. This awareness (or knowledge) may then be used to enable the termination of paths much earlier in the topology, thus freeing links that would otherwise be (unnecessarily) utilized.
- an attempt to establish connection 250 from the SD C 1 to the controller 112 1 may result in establishing a partial path all the way from the SD C 1 to the expander 122 A —e.g., the SD C 1 may send an equal/low priority OAF destined for the controller 112 1 , which may traverse, within the topology 100 , the expander 122 C to the expander 122 B and then to the expander 122 A (thus resulting in utilization of one of the available upstream links between the expander 122 C and the expander 122 B , and between the expander 122 B and the expander 122 A .
- the expander 122 A may then determine that there are no available links to the controller 110 1 , and accordingly may respond (to the SD C 1 ) by sending arbitration-in-progress (AIP) responses to connection requests received therefrom, indicating that all the upstream links of the expander 122 A towards the controller 112 1 are occupied.
- AIP arbitration-in-progress
- the arbitration-in-progress (AIP) responses may propagate through the partial path all the way from the expander 122 A to the SD C 1 (i.e., through the expander 122 B and the expander 122 ).
- the expanders receiving the AIP responses may utilize these messages in generating and/or updating link utilization related information (e.g., local databases), which may be used in handling subsequent connection requests.
- each of the expanders 122 B and 122 C may generate or update local link utilization related parameters (e.g., in a database), based on the AIPs responses, from the expander 122 A , to the OAF for attempted connection 250 —e.g., to note that connectivity to the controller 112 1 via the expander 122 A is not possible due to utilization of all available links therebetween.
- local link utilization related parameters e.g., in a database
- the expander 122 C may maintain a local link utilization database (e.g., tracking all pending connection requests routed through it and/or previously received AIP responses), which may enable it to have knowledge of link unavailability with respect to a particular node in the topology (e.g., unavailability of links between the expander 122 A and the controller 112 1 ).
- a local link utilization database e.g., tracking all pending connection requests routed through it and/or previously received AIP responses
- the expander 122 C may check its local link utilization database.
- the pending connection (or AIP response corresponding thereto) of SD C 1 for the controller 112 1 i.e.
- the expander 122 C may not forward the OAF requests of SD C 4 on the available outgoing links to the next destination (i.e., to the expander 122 B ). Rather, the expander 122 C may generate (locally) AIP responses and send them back to the SD C 4 . In other words, the expander 122 C would only forward (to next nodes in the topology 100 ) the OAF request destined for the controller 112 1 only when there is no pending connection request for the controller 112 1 through it.
- the expander 122 B may maintain a link utilization database (e.g., tracking all pending connection requests routed through it and/or previously received AIP responses), which may enable it to have knowledge of link unavailability with respect to a particular node in the topology (e.g., unavailability of links between the expander 122 A and the controller 112 1 .
- a link utilization database e.g., tracking all pending connection requests routed through it and/or previously received AIP responses
- the expander 122 B may still be able to do so.
- the expander 122 B may check its own local link utilization database, and when the pending connection request (or AIP response corresponding thereto) of SD C 1 for the controller 112 1 (i.e. for connection 250 ) is found, the expander 122 B may not forward the OAF requests of SD C 4 on the available outgoing links to the next destination (i.e., to the expander 122 A ). Rather, the expander 122 B may generate (its own) AIP responses and send them back to the SD C 4 . In other words, the expander 122 B would only forward (to next nodes in the topology 100 ) the OAF request destined for the controller 112 1 only when there is no pending connection requests for the controller 112 1 through it.
- the list link between the expander 122 B and the next node (the expander 122 A ) would not be used (unnecessarily) for pending connection 260 , and would remain available.
- the SD D 4 sends requests for establishing connection 270 to the controller 112 2 , the request may be completed successfully (using available links between the expander 122 B and the expander 122 A , then between the expander 122 A and the controller 112 2 ), and the SD D 4 may continue with its IO traffic.
- incorporating the ability to block pending connections earlier in the topology 100 would result in enhanced connection routing by the expanders, enhanced link utilization throughout the topology, and ultimately improve the IO throughput performance in the topology.
- FIGS. 3A and 3B illustrate an example use of a link utilization enhancement scheme in a Serial Attached SCSI (SAS) based networking topology, based on sharing of link related data.
- SAS Serial Attached SCSI
- nodes in the topology 100 may share link related information, which may be used (by other nodes) in assessing link availability/unavailability within the topology, and/or make determinations based therein regarding whether connectivity to particular target nodes are (not) possible.
- each of the expanders 122 A , 122 B , 122 C , and 122 D may be configured to communicate (e.g., using unicast or broadcast messages) to other expanders in the topology 100 link related information.
- the information may comprise total number of links to other nodes, updates on utilized/freed links, and the like.
- the expander 122 A may send to the expander 122 B a link related message indicating that it has two upstream links to the controller 112 1 and four upstream links to the controller 112 2 .
- the expander 122 B may determine after connections 310 and 320 are established from the SDs SD B 2 and C 2 , respectively to the controller 112 1 , through the expanders 122 B and 122 A , that there are no further links available to the controller 112 1 through the expander 122 A .
- expander 122 B while doing topology discovery (using SMP Message/Request), can create a link available table for all the devices including controller 112 1 and it can also maintain link utilized table for each device based on the active connection though the expander (for the device) and using these two table/info expander 122 B can find that number of link of the controller 122 A is already utilized. Accordingly, the expander 122 B may locally handle further OAFs targeted for the controller 112 1 (e.g., by directly sending AIP responses). Thus, as shown in FIG. 3A , when the expander 122 B receives OAF requests from the SD B 1 (for connection 330 ) and the SD C 4 (for connection 340 ), it may handle them directly, sending AIP responses back to both SDs.
- connections 350 and 360 subsequently may be setup successfully from the SDs D 1 and D 4 to the controller 112 2 , through the expanders 122 B and 122 A .
- the broader the scope of information sharing is, the more that handling can be localized, thus resulting in more enhanced link utilization. For example, if the link related message from the expander 122 A was broadcast within the topology, thus reaching the expander 122 C , some requests may be handled even earlier in the topology. Thus, based on that message, the expander 122 C may update its link database to indicate that the expander 122 A has only two links to the controller 112 1 .
- the expander 122 C may directly handle subsequent requests for connections to the controller 112 1 through the expander 122 A —e.g., as shown in FIG. 3B , the expander 122 C may directly handle the OAF requests received from the SD C 4 (for connection 340 ), such as by generating and sending back directly AIP responses.
- FIG. 4 is a flowchart illustrating an example process for handling connection requests in a SAS topology incorporating use of enhanced link utilization. Referring to FIG. 4 , there is shown a flow chart 400 , comprising a plurality of example steps.
- a SAS topology (e.g., the SAS topology 100 ) may be setup and/or configured.
- the SAS topology may be setup using a plurality of network devices, which may be configured to run or perform various functions, including SAS expanders, SAS controllers, and SAS devices (SDs).
- SDs SAS devices
- a SAS expander (e.g., the SAS expander 122 B in the topology 100 ) may receive a connection request (e.g., in the form of OAF), which may originate from a particular SAS device, and may be destined for particular target device (e.g., particular SAS controller, such as the SAS controller 112 2 in the topology 100 ).
- a connection request e.g., in the form of OAF
- target device e.g., particular SAS controller, such as the SAS controller 112 2 in the topology 100.
- the SAS expander may determine if it has any available links to the next node in the topology that would need to be traversed to reach the specified destination. If no available links are available, the process may jump to step 412 ; otherwise, the process may proceed to step 408 .
- the SAS expander may determine whether there are any pending connection requests through that SAS expander. If there are no other connection requests currently pending in the SAS expander, the process may jump to step 416 ; otherwise, the process may proceed to step 410 .
- the SAS expander may determine whether the received connection request matches any of the currently pending connection requests. For example, the SAS expander may compare the received OAF with the pending connection requests. In this regard, the SAS expander may compare, for example, the destination SAS address in the received OAF with destination SAS addressees of all currently pending connection requests.
- a successful match may be made based on particular criteria—e.g., if the destination SAS address of a pending connection request matches with the destination SAS address in the received OAF, the pending connection request has higher priority, and the SAS expander is currently receiving AIP responses for that pending connection request. If there are no successful matches with any of the currently pending connection requests in the SAS expander, the process may jump to step 416 ; otherwise, the process may proceed to step 412 .
- steps 408 and 410 are described herein as being based on pending (other) connection requests, the process is not so limited, and other parameters (and checks based thereon) may be used in lieu of (or in addition to) these checks to ascertain link utilization in the topology (including in other nodes upstream for the current nodes). This may include, for example, checks based on link utilization data as obtained from update messages communicated (as unicast or broadcast messages) to the present node.
- the SAS expander would not forward the received OAF to the destination (even if there are available links to the next node in the topology). Rather, the SAS expander may locally handle the received OAF. For example, the SAS expander may perform an arbitration process, and may generate and forward (send back) AIP responses (on the incoming link of the received OAF) to the originator. The SAS expander may continue to do so for as long as the condition—i.e., reception of AIP responses for the matched pending connection request(s)—persists, such as by continually checking (in step 414 ) the link utilization in the topology (e.g., re-check pending connection requests, updates from other nodes, etc.). When the condition is resolved, the process may proceed to step 416 .
- the condition i.e., reception of AIP responses for the matched pending connection request(s)—persists, such as by continually checking (in step 414 ) the link utilization in the topology (e.g., re-check pending connection
- the OAF request may be forwarded to the next node (e.g., next SAS expander, such as the SAS expander 122 A in the topology 100 ), thus extending the path.
- next node e.g., next SAS expander, such as the SAS expander 122 A in the topology 100
- implementations may provide a non-transitory computer readable medium and/or storage medium, and/or a non-transitory machine readable medium and/or storage medium, having stored thereon, a machine code and/or a computer program having at least one code section executable by a machine and/or a computer, thereby causing the machine and/or computer to perform the steps as described herein for enhancing active link utilization for SAS topology.
- the present method and/or system may be realized in hardware, software, or a combination of hardware and software.
- the present method and/or system may be realized in a centralized fashion in at least one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other system adapted for carrying out the methods described herein is suited.
- a typical combination of hardware and software may be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.
- Another typical implementation may comprise an application specific integrated circuit or chip.
- the present method and/or system may also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods.
- Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.
- some implementations may comprise a non-transitory machine-readable (e.g., computer readable) medium (e.g., FLASH drive, optical disk, magnetic storage disk, or the like) having stored thereon one or more lines of code executable by a machine, thereby causing the machine to perform processes as described herein.
- a non-transitory machine-readable (e.g., computer readable) medium e.g., FLASH drive, optical disk, magnetic storage disk, or the like
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Abstract
Description
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11175855B2 (en) | 2018-11-09 | 2021-11-16 | Samsung Electronics Co., Ltd. | Electronic device for communicating with host and operating method of the electronic device |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3093830B1 (en) * | 2019-03-11 | 2021-03-12 | St Microelectronics Rousset | Method for managing access to a shared bus, and corresponding electronic device |
US11914537B2 (en) * | 2021-04-15 | 2024-02-27 | Apple Inc. | Techniques for load balancing with a hub device and multiple endpoints |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050249495A1 (en) * | 2002-04-11 | 2005-11-10 | Beshai Maged E | Fast optical switch |
US20060187829A1 (en) * | 2005-02-07 | 2006-08-24 | Nokia Corporation | Distributed connection admission-control |
US7836360B2 (en) * | 2007-04-09 | 2010-11-16 | International Business Machines Corporation | System and method for intrusion prevention high availability fail over |
US20110187829A1 (en) * | 2010-02-01 | 2011-08-04 | Casio Computer Co., Ltd. | Image capture apparatus, image capture method and computer readable medium |
US20120236707A1 (en) * | 2011-03-16 | 2012-09-20 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and Arrangement for Managing Radio Link Failure |
-
2014
- 2014-02-17 US US14/182,008 patent/US9270756B2/en active Active
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050249495A1 (en) * | 2002-04-11 | 2005-11-10 | Beshai Maged E | Fast optical switch |
US20060187829A1 (en) * | 2005-02-07 | 2006-08-24 | Nokia Corporation | Distributed connection admission-control |
US7502371B2 (en) * | 2005-02-07 | 2009-03-10 | Nokia Corporation | Distributed connection admission-control |
US7836360B2 (en) * | 2007-04-09 | 2010-11-16 | International Business Machines Corporation | System and method for intrusion prevention high availability fail over |
US20110187829A1 (en) * | 2010-02-01 | 2011-08-04 | Casio Computer Co., Ltd. | Image capture apparatus, image capture method and computer readable medium |
US20120236707A1 (en) * | 2011-03-16 | 2012-09-20 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and Arrangement for Managing Radio Link Failure |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11175855B2 (en) | 2018-11-09 | 2021-11-16 | Samsung Electronics Co., Ltd. | Electronic device for communicating with host and operating method of the electronic device |
US11593033B2 (en) | 2018-11-09 | 2023-02-28 | Samsung Electronics Co., Ltd. | Electronic device for communicating with host and operating method of the electronic device |
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