Session idle optimization for streaming server

Graphics rendering services may be provided to a client device by a remote computing facility. One or more rendering processes may be executed on a virtual machine operating on a host computing device. Client state information may be monitored to detect periods of inactivity. A rendering process may be inactivated by suspending the virtual machine on which it executes. Upon resumption of activity, the rendering process may be reactivated by resuming execution of the virtual machine.

CROSS REFERENCE TO RELATED APPLICATIONS

BACKGROUND

Computing devices such as mobile phones, tablet computers, game consoles and so forth may not be equipped to render graphics with speed and detail sufficient for certain applications. Rendering graphics, which may be described as a process for generating images for use in games and other computer applications, may utilize specialized computing resources such as graphics processing units that may not be available on a computing device. In some cases, resources may be available but would consume excess power, or would run at an insufficient speed or provide an insufficient level of graphical quality.

Graphics rendering capabilities may be provided to a client device by computing resources located at a remote facility. The facility may, for example, be equipped with banks of graphical processing units (“GPUs”) or other hardware specialized for the provision of rendering services. However, even with the use of specialized hardware, the provision of graphics rendering services may consume significant amounts of computing resources. For example, graphics rendering may involve loading various models, textures, bitmaps and so forth into memory. These resources may be retained in memory while a dependent process is running on a client device. Management of resource utilization may improve the performance and efficiency of the rendering service.

DETAILED DESCRIPTION

In accordance with some example features of the disclosed techniques, one or more rendered views of a scene of a particular content item, such as a video game, may be generated by a content provider and transmitted from the provider to multiple different clients. In some cases, a content provider may generate multiple views of a scene or virtual environment of a particular content item. Each of the multiple views may, for example, be associated with one or more respective clients and may be transmitted from the content provider to the respective clients. For example, each view may present scenes from a viewpoint of a particular character or other entity controlled by a respective client to which the view is transmitted. The views may be based on a shared state of a game or other video content maintained by the content provider. In some cases, the content provider may transmit an identical view of a scene of a particular content item to multiple clients. Identical views may, for example, be transmitted to clients viewing a game from the viewpoint of a particular character.

A content provider may provide rendering services through rendering processes. In some cases and embodiments, a rendering process may correspond to an instance of an executable application. However, a rendering process may instead comprise component invocations, library calls, objects, multiple instances of an executable application and so on.

A rendering process may be associated with a set of one or more clients. Each client may in turn be associated with one or more users. A rendering process may be associated with a particular content item, such as a game, animation, television program and so forth. A rendering process may also be associated with an instance of a content item. For example, a multiplayer game may provide interaction between a set of clients. In such cases, embodiments may associate a rendering process with the set of clients. In some cases and embodiments, multiple rendering processes may be associated with an instance of a game, and each rendering process associated with one or more clients. This approach might be employed, for example, in a massively multiplayer game or a group viewing of a movie or television show.

To enable generation of a single shared state of display content and to select, from within that state, the one or more views of a scene, each of the different participating clients may collect respective client state information. The client state information may include, for example, information regarding operations performed at the respective client such as movements or other actions performed by a respective character or other entity controlled by the respective client. A client may periodically transmit an update of its respective client state information to the content provider. The content provider may then use the client state information updates received from each client to update shared content item state information maintained by the content provider. The content provider may then use the shared content item state information to generate the one or more views transmitted to the different participating clients.

Client state information may also include information related to or reflective of input by a user of a client. For example, a user of a client may press a button, move a joystick, speak into a microphone and so forth. Input from a client, such as the examples presented, may result in movements or other actions performed by a respective character or other entity controlled by the respective client. In some cases and embodiments, input may not be related to a control of a game character. Input could also correspond to the presence of a user. For example, a motion-sensitive camera might indicate that a user of the client is present.

In some embodiments, client state information may comprise information about spectator status, recording status, and so on. For example, a user may be a spectator in a multiplayer game, in which case client state information may contain information indicating the presence of the spectator, even though the spectator might not be providing input to the client, or is providing input intermittently. In another embodiment, a client device might be recording information, in which case client state information might comprise an indication that transmitted content is being recorded. Some embodiments may utilize rendering services to enable viewing of movies, television, sporting events and so forth. In one such embodiment, client state information may pertain to receiving textual, audio, or other input from a user commenting on the displayed content.

Receipt of client state information may be indicative of starting, resuming or continuing an active state of a rendering process associated with one or more clients. The content provider or rendering process may receive various transmissions or messages containing data corresponding to or indicative of client state information. Client state information indicative of an active state of a rendering process includes, but is not limited to, input by a user, presence of a user, a spectator state, a recording state and so on.

A rendering process may be executed on an instance of a virtual machine, or on other types of computing nodes in addition to virtual machine instances. Virtual machine instances may also be referred to as virtual machines. In some embodiments, there may be a one-to-one association of a rendering process to a computing node. In other embodiments, multiple rendering processes may be executed on the same computing node. Embodiments may associate rendering processes corresponding to a same content item to the same computing node. This approach may enable rendering processes to share content-related graphics resources.

A content provider may improve efficiency of its operations by maximizing computing resources available to rendering processes that are active. A virtual machine on which a rendering process executes may consume resources that might otherwise be available to other virtual machines executing other rendering processes. In order to maximize computing resources available to virtual machines running active rendering processes, those virtual machines that are running inactive rendering processes may be suspended. An inactive rendering process may be an executing process whose state of execution is retained in the state of the suspended virtual machine.

An inactive rendering process may include rendering processes whose clients do not have a current need for rendering services. In various cases and embodiments, client state information may be received by the content provider. The client state information may be indicative of a current need for rendering services, which may for example correspond to factors such as movement of an element of the content, input by a user of a client, spectator mode, recording mode and so on. In various cases and embodiments, a pause in receiving client state information may be indicative of no current need for rendering services. This might occur, for example, when a client device has shut down. Another possibility is that a client state may have changed so that rendering services are no longer needed. For example, a game running on the client may have ended and a new game has not yet started.

FIG. 1depicts an example, consistent with aspects of the present embodiment, of a system for managing rendering processes on virtual machines. User114may interact with client116. A client may comprise a hardware device such as a mobile phone, tablet, gaming console, personal computer and so on. The client may also comprise application programs118, operating system or other software modules, in various combinations. A client may also comprise a rendering service application programming interface (“API”)120, which may provide client process118with access to a rendering process, such as rendering process104. Client processes may also communicate with a rendering process directly. For example, client process124might communicate with rendering process110, or invoke a function of rendering service API126to communicate with rendering process110.

Access to rendering process104may be direct or indirect. For example, direct access could include client116communicating with rendering process104through network112. Indirect access could include client122accessing rendering process110through content provider100. In some embodiments, a proxy132may operate within content provider100to broker access to rendering processes, such as rendering process110. A proxy might also operate within virtual machine102or virtual machine108.

Multiple users such as user128and user130may interact with a client such as client122. Interaction with a client, such as client122, may comprise various actions and events. Non-limiting examples of interactions include game controller movements, microphone input, camera input and so on. Interactions may be incorporated into client state information. Client state information may comprise information indicative of a number of users of a client. The information may include information that allows deduction of the number of active users. For example, client state information may comprise actions by a number of users. A number of clients may be inferred based on a time-to-last metric corresponding to an input action by a user of a client, such as user128or user130of client122. A count of active users associated with a client may be used to determine whether to maintain an active state of a rendering process, such as rendering process110on virtual machine108. For example, if user128and user130cease interacting with client122, rendering process110might enter into an inactive state to minimize resource consumption. This might be accomplished, for example, by suspending virtual machine108. Another possibility is that both user128and user130activate a pause function for client process124. This might occur, for example, by users128and130both switching to an alternative application.

FIG. 2depicts an embodiment of a client200comprising at least one client process202and at least one rendering service API204. Client process202may comprise one or more modules implementing various aspects of an application's functionality. Applications include, but are not limited to, video games, video playback services, video editing, animation, simulation and so forth. Modules may include any combination of computer-readable instructions, circuitry, and so forth. A module may, for example, include statically and dynamically linked libraries, business objects, component objects, graphics processing units, physics processing units and so on.

A rendering service API may act as a component of client process202. It may comprise one or more modules implementing various pieces of functionality. Although rendering service API204is depicted inFIG. 2as containing various modules implementing specific pieces of functionality, such as application shutdown206, those of ordinary skill in the art will appreciate that various combinations comprising additions, subtractions, substitutions and rearrangements are possible.

Application shutdown206depicts a module of rendering service API204that receives indications related to the running state of client process202. It may, for example, receive a notification that client process202is going to be shut down, suspended or paused. It may then send notification to a content provider, which includes any proxy or rendering processes operated within the content provider. The notification indicates that services associated with that application may be suspended.

User input monitoring208may involve tracking user activity related to client process202. It may also involve representing user activity as client state information, which may be transmitted from the client to a content provider.

Service utilization control210may involve monitoring or responding to events affecting a level of rendering processes likely to be requested by client process202. These events include transitions of game state, such as from a state involving activate gameplay to a state involving display of a pre-rendered scene, for which rendering services are not presently required. The events may be controlled by client process202via function calls, method calls or similar techniques, invoked on a module of rendering service API204. Service utilization events may be sent, for example as client state information, to a content provider.

Hardware events212may detect and respond to various hardware events, including but not limited to client device shutdown, controller shutdown, display shutdown, system suspend, system resume, and so on. These events may also be indicative of a level of rendering processes likely to be requested by client process202. Information indicative of hardware events may be transmitted, for example as client state information, to a content provider.

Service utilization statistics214may relate to collection of information pertaining to use of rendering services by the game, the game's publisher, hardware provider or other entity. In some embodiments, certain aspects of these services may be performed directly by rendering service API204. This might, for example, include causing reports to be generated and/or transmitted. The reports might pertain to various usage statistics such as a level of usage performed on behalf of a particular client. In some embodiments, service utilization statistics214may indirectly participate in generation of relevant statistics, for example by transmitting identifying information to a content provider. Identifying information may include user information, client device information, game information, publisher information and so on. Cryptographic techniques may be employed to prevent tampering with a provided identity.

Service relocation216may pertain to re-association of a content provider, proxy, virtual machine, or rendering process with a different address, such as a different internet protocol (“IP”) address. Re-association may occur based on various events, such as utilization balancing, failover or other scenarios. For example, a state corresponding to a suspended virtual machine might be moved from one host to another, and be assigned a different IP address after the move. Embodiments might also relocate a rendering process from one virtual machine to another.

FIG. 3depicts an embodiment of a content provider300hosting rendering services on virtual machine302. AlthoughFIG. 3depicts one virtual machine, content providers may host a number of virtual machines. A content provider may include one or more computing facilities such as data centers, clusters of servers, individual servers and so on. Various virtual machines may operate within a content provider. For example, a computing facility may operate various computing hosts, on which a hypervisor and one or more virtual machines operate. Various control facilities may be employed to create, remove, shut down, restart, suspend and reactivate virtual machines.

A content provider may manage state information for virtual machines. A virtual machine may have an associated state which may be stored on a storage device. The state for a suspended or shut down virtual machine may be stored in a low-latency cache. A low-latency cache includes, but is not limited to, random access memory, in-memory databases, solid-state storage devices and so forth. The state for a suspended virtual machine may also be stored on a storage device that, compared to low-latency options, may be described as high-latency. Distinctions between low-latency and high-latency storage options may be based on factors other than qualities of an underlying storage device. Instead, in some embodiments low and high latency storage may be distinguished by overall system latency, which may be influenced by factors such as network speed, traffic congestion and so on.

A rendering process304may be assigned to operate on virtual machine302. The rendering process may provide various services related to graphics processing, such as managing graphics resources, and rendering graphical scenes. A render process may perform one or more steps of a rendering pipeline. A rendering pipeline may comprise various data structures, resources, and stages such as shape buffers, vertex buffers, textures buffers, input assembly, texture mapping, shading, render targets and so forth. Embodiments may include support for various types of pipelines, including but not limited to 2-dimensional and 3-dimensional rendering, physics processing pipelines and so on.

Various modules may perform functions related to operation of rendering process304. AlthoughFIG. 3depicts these modules as distinct entities, it will be appreciated that the depicted modules may be reordered, rearranged, combined, altered or omitted in various combinations. In addition, although depicted inFIG. 3as elements distinct from rendering process304and virtual machine302, some or all of the functions performed by the depicted modules may be performed by rendering process304and/or virtual machine302.

A module for client state monitoring306may receive and/or process client state information pertaining to a client of a rendering process. Embodiments may monitor client state information to determine the presence or absence of user activity, and may further classify the activity as being indicative of maintaining an active state of a rendering process associated with the client. An active state of a rendering process may be indicated by factors such as user input, requests by a client to maintain an active state despite a period of inactivity, initialization of a new application on a client and so forth. A rendering process may be maintained in an active state based on receipt of information indicative of activity on a client, which may be transmitted to a content provider as client state information. Activity on a client may refer, for example, to receipt of user input, requests for rendering services, active execution of a rendering process and so forth.

Client state information may also be indicative of transitioning to an inactive state. A lack of activity may correspond to various conditions which may suggest transitioning to an inactive state of the rendering process. For example, a dropped network connection may interrupt communication between a rendering process and a client, in which case embodiments may cause the rendering process to transition to an inactive state. Client state monitoring306may track or receive information pertaining to a last time user input, initialization of a new application or other information pertaining to client activity was received. If this time exceeds a threshold, client state monitoring306may determine that rendering process304should enter into an inactive state. Embodiments may, upon receiving information corresponding to an active state of a rendering process, cause an inactive rendering process to transition to an active state.

A rendering process may transition to an active state by suspending the virtual machine on which it runs. In some embodiments, a suspended virtual machine may remain in its host's primary memory, but not consume central processing unit cycles. In another embodiment, a state for a suspended virtual machine may be stored in a low-latency cache, or on other forms of storage devices. In another embodiment, a state for a suspended virtual machine may transition from in-memory to low-latency cache to higher-latency storage, based on the period of time a corresponding rendering process has been inactive. A latency minimization module308may perform various actions to minimize latency in accessing rendering processes. These actions may include, but are not limited to, moving a state of a suspended virtual machine to or from main memory, cache, or relatively high-latency storage, based on a state of a client associated with a rendering process executing on a virtual machine.

A capacity and utilization management module310may perform various actions to improve resource utilization. In some cases and embodiments, virtual machine302might host a number of rendering processes. Embodiments may assign rendering processes to a virtual machine based on factors including, but not limited to, a common client device, a common user, a common set of game content and so forth. Embodiments may also attempt to improve factors such as resource utilization, latency and so forth by assigning rendering processes to virtual machines in accordance with improving these factors. In some embodiments, capacity and utilization management310may involve assigning rendering processes and/or virtual machines to computing resources based on processing power of those resources. For example, in some cases and embodiments client state information might contain an indication of a requested level of rendering services. Based on the indication, a virtual machine host might be selected to operate a rendering process, based partly on processing power available to the selected host.

Another module may perform various actions related to capacity and utilization statistics312. These actions may include maintaining records on rendering services provided to a user, client, application, application publisher and so forth. In some embodiments, content providers may monitor usage statistics such as throughput, pages rendered, CPU cycles consumed and so forth. Content providers may employ various usage statistics such as these to impose a service charge on entities such as a game publisher.

FIG. 4depicts an embodiment of a process for managing rendering processes. Although depicted as a sequence of operations, those of ordinary skill in the art will appreciate that the depicted order should not be construed as limiting the scope of the present disclosure and that at least some of the depicted operations may be altered, omitted, reordered or performed in parallel.

Operation400may involve receiving information indicative of providing rendering services to a client. Embodiments may receive client state information corresponding to initialization of an application that will use rendering services. The initialized application instance, and/or the client on which it runs, may be associated with a rendering process. Embodiments may perform a mapping or lookup operation to determine if an application instance and/or client is already associated with a rendering process. If not, a new rendering process may be created.

Operation402depicts allocating a virtual machine on which the rendering process may execute. Allocating a virtual machine may involve reusing an existing instance of a virtual machine, creating a new instance, copying a pre-existing instance and so on. Embodiments may, for example, form a copy of a pre-defined image of a virtual machine state, where the pre-defined image corresponds to an initial state of a virtual machine that is configured to execute a rendering process. In some embodiments, an image of a virtual machine may be used in which a rendering process has already begun executing but has not yet served any clients. In some cases and embodiments, a virtual machine image may contain a rendering process that has begun executing and has loaded resources corresponding to a particular application, such as a specific game program. The virtual image may be recorded at that point, after resource loading but prior to having provided services to a client. Images corresponding to virtual machines in these and other initial states may be stored and subsequently loaded when preparing a virtual machine to provide rendering services to a client.

A virtual machine may be allocated for executing a rendering process based on the virtual machine having access to graphics resources associated with a process, such as a game, running on a client of the rendering services. The game running on the client may rely on graphics resources accessible to the rendering process executing on the virtual machine. Having access to graphics resources may include connectivity to storage devices having the graphics resources stored thereon. Another possible variation, among many, includes a virtual machine image in which a rendering process has pre-loaded graphics resources related to the game or other application.

Operation404depicts associating a rendering process executing on a virtual machine with a client. Embodiments may maintain a record of an association between a client and the rendering process and/or the virtual machine on which the rendering process operates. The association may be maintained, in some embodiments, in a database or other data store operating independently of the virtual machine. Received client state information may be correlated with a rendering process based on the recorded association. For example, client state information might be received by a content provider and the corresponding rendering process could be determined based on the recorded association.

A rendering process may be described as executing on or operating on a virtual machine. The terms “executing on” and “operating on” are intended to encompass a variety of states in which a rendering process begins or continues execution on a virtual machine.

Operation406depicts receiving information indicative of transitioning a rendering process to an inactive state. Embodiments may determine that a rendering process should transition to an inactive state based on a predicted maximum period of inactivity being exceeded. In various embodiments, a time may be recorded to indicate when client state information was last received, where the client state information indicates that a corresponding rendering process should remain active. Embodiments may then compare the amount of time since last receiving such information to a threshold amount of time. If the amount of time exceeds the threshold level, embodiments may transition a rendering process to an inactive state. A predicted maximum period of inactivity may be used as the threshold. The predicted maximum may be a fixed value or a dynamic value determined based in part on prior periods of activity or inactivity.

Operation408depicts suspending a virtual machine to deactivate a rendering process operating on the virtual machine. In some embodiments, the suspending virtual machine may remain in the primary memory of its host but its virtual processors may cease execution. In another embodiment, the virtual machine may be removed from memory and stored on a storage device. Embodiments may, for example, store a state corresponding to the virtual machine in a low-latency cache, or on other storage devices. Embodiments may perform various combinations of these actions. For example, embodiments may determine to perform one of these actions based on an expected or predicted period of inactivity by the client. For example, if client state information indicates that a game has entered a known period of inactivity (for example when a pre-rendered video is being displayed), the virtual machine might remain inactive but in memory. On the other hand, if a client has been turned off, the virtual machine might be moved to a comparatively high-latency storage device, or deleted.

A virtual machine may be suspended upon determining that a number of active rendering processes on the virtual machine has fallen below a threshold level. In some embodiments, such as those that map rendering processes to virtual machines on a one-to-one basis, the threshold level may be one. Other embodiments may host multiple rendering processes on a virtual machine. Embodiments may therefore suspend the virtual machine when all rendering processes hosted by the virtual machine have become inactive. Further embodiments may transfer active rendering processes to another virtual machine when the number of active rendering processes falls below a threshold number.

Operation410depicts receiving information indicative of transitioning a rendering process from an inactive state to an active state. For example, a rendering process may have been deactivated based on a pause event. Upon receiving client state information indicating that the client has been un-paused, a rendering process associated with the client may be reactivated.

Operation412depicts reactivating a rendering process by reactivating the virtual machine on which the rendering process was executing. Reactivating the virtual machine may comprise steps such as retrieving a state for the virtual machine from storage or from a low-latency cache. Reactivation may also comprise resuming execution of virtual processors associated with the virtual machine. A content provider may send status information pertaining to resuming operations of a rendering service. For example, a content provider might send a client information that is indicative of the amount of time resuming operation of the rendering service is expected to take. This might include, for example, estimated time to completion, percent complete and so forth.

FIG. 5depicts another embodiment of a process for managing rendering processes. Although depicted as a sequence of operations, those of ordinary skill in the art will appreciate that the depicted order should not be construed as limiting the scope of the present disclosure and that at least some of the depicted operations may be altered, omitted, reordered or performed in parallel.

A client may be associated with a rendering process which may provide rendering services to the client. The rendering process may be executed on a virtual machine selected based on a variety of factors. Operations500through506depict non-limiting examples of factors that may be used to associate a client with a rendering process and/or to select a virtual machine to execute the rendering process.

Operation500depicts associating clients to a rendering process on a one-to-one basis, so that each client is mapped to a rendering process that provides rendering services only to that client. Embodiments may also map rendering processes on a one-to-one-basis to an application, so that a given rendering process provides rendering services only to one application. In some embodiments, multiple rendering processes may be assigned to a client, or multiple clients to one rendering service.

Operation502depicts associating a client with a rendering process that is pre-configured to render requested content. For example, embodiments might retain an image for a virtual machine in a state in which a rendering process had begun executing in preparation for providing rendering services related to specific content, such as a particular game application. This may allow various wireframes, textures, and so forth to be pre-loaded prior to an association between a rendering service and a client.

Operation504depicts determining to execute a rendering process on a virtual machine that is selected based on the content being rendered by other processes executing on the same virtual machine. This approach may allow memory blocks containing graphical resources to be shared among multiple rendering processes providing rendering services for the same content.

Operation506depicts executing a rendering process on a virtual machine that is selected based on grouping rendering processes for a particular client on one virtual machine, or on a minimized number of virtual machines. For example, a client might execute two applications, each of which requires rendering services. An application might then be associated with its own, dedicated rendering process. These rendering processes may be grouped so as to execute on the same virtual machine. In some embodiments, rendering processes associated with the same client are grouped on a virtual machine, so that rendering processes associated with other clients are excluded from that virtual machine.

Operation508depicts managing active and inactive states of rendering processes executing on virtual machines. This may comprise suspending a virtual machine in order to deactivate one or more rendering processes operating on the virtual machine. In some embodiments, where multiple rendering processes are employed, the virtual machine may be suspended when all rendering processes should transition to an inactive state. Embodiments may leave all rendering processes operating on a virtual machine in an active state until each rendering process is able to transition to an inactive state, and then suspend the virtual machine. Embodiments may determine to transition a rendering process to an inactive state when various events occur, including but not limited to a delay in receiving client state information indicative of a need for rendering services.

Embodiments may employ various approaches to prepare virtual machines for executing rendering processes.FIG. 6depicts an embodiment of a process for maintaining pools of virtual machines. Although depicted as involving a sequence of operations, those of ordinary skill in the art will appreciate that the depicted order should not be construed as limiting the scope of the present disclosure and that at least some of the depicted operations may be altered, omitted, reordered or performed in parallel.

Virtual machine initialization600involves various aspects of creating, starting, and configuring virtual machines for use in executing a rendering process. Various operations, such as those depicted by operations602,604, and606may be performed to instantiate virtual machines for use in executing a rendering process. The operations depicted by602,604, and606may be combined in various ways to form further embodiments of the present disclosure.

Operation602depicts retrieving state information for a virtual machine configured to execute a rendering process. A virtual machine state may be stored as a file, and may sometimes be referred to as a virtual machine image. In various embodiments, the virtual machine state may correspond to a virtual machine that has been pre-configured to execute a rendering process. For example, the virtual machine may have an installed operating system. Any files used to execute a rendering process may have already been copied to the virtual machine, and any necessary configuration steps performed.

Operation604depicts retrieving state information for a virtual machine that is already executing a rendering process. Embodiments may utilize a virtual machine image in which the state of the machine reflects a rendering process that is currently executing but not yet associated with or providing service to a client.

Operation606depicts retrieving state information for a virtual machine configured to execute (or already executing) a rendering process related to specific content. For example, a virtual machine image might be saved at a point in which a rendering process has begun executing and has loaded resources for a particular application, such as a game. The resources might include bitmaps, textures, wire-frame models and so on.

Embodiments may select a virtual machine from the pool based on the selected virtual machine being configured to execute a rendering processes having access to graphics resources related to the application for which graphics rendering services are being provided. In some cases, a rendering process may be specifically configured to have access to the graphics resources. In other cases the selected virtual machine may be configured to have access to the graphics resources.

Pool organization608refers to various operations that may be performed to form pools of virtual machines for executing rendering processes. As used herein, the term pool may refer to various collections of objects, such as collections of virtual machines. The collections may be organized by data structures such as lists or arrays, or by various classification methods. In various embodiments, a pool may be a collection or set of objects or resources which may be withdrawn from the pool as needed. For example, a pool may contain a set of unused virtual machines that may be withdrawn from the pool and used to execute a rendering process.

Operation610depicts maintaining a pool of virtual machines. Maintaining a pool may involve creating virtual machines, placing the virtual machines in the pool, withdrawing virtual machines from the pool and returning the virtual machines to the pool. Embodiments may maintain a minimum and/or maximum number of free virtual machines in the pool.

Operation612depicts maintaining a pool of virtual machines based on content. This may involve classifying virtual machines in the pool as belonging to a particular set of content. When a virtual machine is withdrawn from the pool, a virtual machine appropriate to the particular content set may be withdrawn. For example, virtual machines configured to pre-load resources for a particular game might be grouped in a pool. When a client requests rendering services for that particular game, a virtual machine from that pool may be used. Clients associated with different applications may obtain virtual machines drawn from a different pool.

Operation614depicts maintaining a pool of virtual machines based on latency minimization. Embodiments may employ a variety of factors to organize such pools. In one embodiment, virtual machines are grouped according to geographic location of each virtual machine's host. Virtual machines may be withdrawn from the pool based on the locations of the hosts and the locations of a client requesting rendering services. Pools may also be organized according to speed, capacity and so on.

Embodiments may combine pools into various combinations of pools and sub-pools. For example, virtual machines could be grouped into pools organized by content, and into sub-pools organized by geographic region.

Pool maintenance616involves various operations performed to withdraw, utilize, and return virtual machines to a pool of virtual machines. As depicted by operation618, a virtual machine may be withdrawn from a pool in order to provide rendering services to a new client. Operation620depicts suspending the virtual machine, without immediately returning it to the pool, to temporarily deactivate a rendering process. At some later time, the virtual machine may be returned to the pool. Operation622depicts one example, in which a virtual machine is returned to a pool upon the disconnection of a client. Some embodiments may delete virtual machines when they are no longer needed. Operation624depicts replenishing the pool of virtual machines, for example by performing one or more of the operations associated with virtual machine initialization600. Virtual machines may be replenished so that a minimum number of virtual machines are kept available in the pool, or to replace virtual machines that have been removed from the pool and subsequently deleted.

A content provider may, in some cases, render and transmit content item views to clients over an electronic network such as the Internet. Content may, in some cases, be provided upon request to clients using, for example, streaming content delivery techniques. An example computing environment that enables rendering and transmission of content to clients will now be described in detail. In particular,FIG. 7illustrates an example computing environment in which the embodiments described herein may be implemented.FIG. 7is a diagram schematically illustrating an example of a data center710that can provide computing resources to users700aand700b(which may be referred herein singularly as user700or in the plural as users700) via user computers702aand702b(which may be referred herein singularly as computer702or in the plural as computers702) via a communications network730. Data center710may be configured to provide computing resources for executing applications on a permanent or an as-needed basis. The computing resources provided by data center710may include various types of resources, such as gateway resources, load balancing resources, routing resources, networking resources, computing resources, volatile and non-volatile memory resources, content delivery resources, data processing resources, data storage resources, data communication resources and the like. A computing resource may be general-purpose or may be available in a number of specific configurations. For example, data processing resources may be available as virtual machine instances that may be configured to provide various web services. In addition, combinations of resources may be made available via a network and may be configured as one or more web services. The instances may be configured to execute applications, including web services, such as application services, media services, database services, processing services, gateway services, storage services, routing services, security services, encryption services, load balancing services, application services and the like. These services may be configurable with set or custom applications and may be configurable in size, execution, cost, latency, type, duration, accessibility and in any other dimension. These web services may be configured as available infrastructure for one or more clients and can include one or more applications configured as a platform or as software for one or more clients. These web services may be made available via one or more communications protocols. Data storage resources may include file storage devices, block storage devices and the like.

Data center710may include servers716a-b(which may be referred herein singularly as server716or in the plural as servers716) that provide computing resources. These resources may be available as bare metal resources, or as virtual machine instances718a-dand (which may be referred herein singularly as virtual machine instance718or in the plural as virtual machine instances718). Virtual machine instances718cand718dare shared state virtual machine (“SSVM”) instances. The SSVM virtual machine instances718cand718dmay be configured to perform all or any portion of the shared content item state techniques and/or any other of the disclosed techniques in accordance with the present disclosure and described in detail below. As should be appreciated, while the particular example illustrated inFIG. 7includes one SSVM virtual machine in each server, this is merely an example. A server may include more than one SSVM virtual machine or may not include any SSVM virtual machines.

Referring toFIG. 7, communications network730may, for example, be a publicly accessible network of linked networks and possibly operated by various distinct parties, such as the Internet. In other embodiments, communications network730may be a private network, such as a corporate or university network that is wholly or partially inaccessible to non-privileged users. In still other embodiments, communications network730may include one or more private networks with access to and/or from the Internet.

Communication network730may provide access to computers702. User computers702may be computers utilized by users700or other customers of data center710. For instance, user computer702aor702bmay be a server, a desktop or laptop personal computer, a tablet computer, a wireless telephone, a personal digital assistant (PDA), an e-book reader, a game console, a set-top box or any other computing device capable of accessing data center710. User computer702aor702bmay connect directly to the Internet (e.g., via a cable modem or a Digital Subscriber Line (DSL)). Although only two user computers702aand702bare depicted, it should be appreciated that there may be multiple user computers.

User computers702may also be utilized to configure aspects of the computing resources provided by data center710. In this regard, data center710might provide a gateway or web interface through which aspects of its operation may be configured through the use of a web browser application program executing on user computer702. Alternately, a stand-alone application program executing on user computer702might access an application programming interface (API) exposed by data center710for performing the configuration operations. Other mechanisms for configuring the operation of various web services available at data center710might also be utilized.

Servers716shown inFIG. 7may be standard servers configured appropriately for providing the computing resources described above and may provide computing resources for executing one or more web services and/or applications. In one embodiment, the computing resources may be virtual machine instances718. A virtual machine instance may be referred to as a virtual machine. As discussed above, each of the virtual machine instances718may be configured to execute all or a portion of an application. In the example of virtual machine instances, Data center710may be configured to execute an instance manager720aor720b(which may be referred herein singularly as instance manager720or in the plural as instance managers720) capable of executing the virtual machine instances718. The instance managers720may be a virtual machine monitor (VMM) or another type of program configured to enable the execution of virtual machine instances718on server716, for example. It will be appreciated that the configuration of instance managers720, as depicted byFIG. 7, is subject to change and that instance managers720may, for example, be configured to operate as a front-end to router714. In some embodiments, instance managers720may be hosted on servers716, or on other computing nodes.

In the example data center710shown inFIG. 1, a router714may be utilized to interconnect the servers716aand716b. Router714may also be connected to gateway740, which is connected to communications network730. Router714may be connected to one or more load balancers, and alone or in combination may manage communications within networks in data center710, for example by forwarding packets or other data communications as appropriate based on characteristics of such communications (e.g., header information including source and/or destination addresses, protocol identifiers, size, processing requirements, etc.) and/or the characteristics of the private network (e.g., routes based on network topology, etc.). It will be appreciated that, for the sake of simplicity, various aspects of the computing systems and other devices of this example are illustrated without showing certain conventional details. Additional computing systems and other devices may be interconnected in other embodiments and may be interconnected in different ways.

It should also be appreciated that data center710described inFIG. 7is merely illustrative and that other implementations might be utilized. Additionally, it should be appreciated that the functionality disclosed herein might be implemented in software, hardware or a combination of software and hardware. Other implementations should be apparent to those skilled in the art. It should also be appreciated that a server, gateway or other computing device may comprise any combination of hardware or software that can interact and perform the described types of functionality, including without limitation desktop or other computers, database servers, network storage devices and other network devices, PDAs, tablets, cellphones, wireless phones, pagers, electronic organizers, Internet appliances, television-based systems (e.g., using set top boxes and/or personal/digital video recorders) and various other consumer products that include appropriate communication capabilities. In addition, the functionality provided by the illustrated modules may in some embodiments be combined in fewer modules or distributed in additional modules. Similarly, in some embodiments the functionality of some of the illustrated modules may not be provided and/or other additional functionality may be available.

In at least some embodiments, a server that implements a portion or all of one or more of the technologies described herein may include a general-purpose computer system that includes or is configured to access one or more computer-accessible media.FIG. 8depicts a general-purpose computer system that includes or is configured to access one or more computer-accessible media. In the illustrated embodiment, computing device800includes one or more processors810a,810band/or810n(which may be referred herein singularly as “a processor10” or in the plural as “the processors810”) coupled to a system memory820via an input/output (I/O) interface830. Computing device800further includes a network interface840coupled to I/O interface830.

In various embodiments, computing device800may be a uniprocessor system including one processor810or a multiprocessor system including several processors10(e.g., two, four, eight or another suitable number). Processors810may be any suitable processors capable of executing instructions. For example, in various embodiments, processors810may be general-purpose or embedded processors implementing any of a variety of instruction set architectures (ISAs), such as the x86, PowerPC, SPARC or MIPS ISAs or any other suitable ISA. In multiprocessor systems, each of processors810may commonly, but not necessarily, implement the same ISA.

In some embodiments, a graphics processing unit (“GPU”)812may participate in providing graphics rendering and/or physics processing capabilities. A GPU may, for example, comprise a highly parallelized processor architecture specialized for graphical computations. In some embodiments, processors810and GPU812may be implemented as one or more of the same type of device.

System memory820may be configured to store instructions and data accessible by processor(s)810. In various embodiments, system memory820may be implemented using any suitable memory technology, such as static random access memory (“SRAM”), synchronous dynamic RAM (“SDRAM”), nonvolatile/Flash®-type memory or any other type of memory. In the illustrated embodiment, program instructions and data implementing one or more desired functions, such as those methods, techniques and data described above, are shown stored within system memory820as code825and data826.

In one embodiment, I/O interface830may be configured to coordinate I/O traffic between processor810, system memory820and any peripherals in the device, including network interface840or other peripheral interfaces. In some embodiments, I/O interface830may perform any necessary protocol, timing or other data transformations to convert data signals from one component (e.g., system memory820) into a format suitable for use by another component (e.g., processor810). In some embodiments, I/O interface830may include support for devices attached through various types of peripheral buses, such as a variant of the Peripheral Component Interconnect (PCI) bus standard or the Universal Serial Bus (USB) standard, for example. In some embodiments, the function of I/O interface830may be split into two or more separate components, such as a north bridge and a south bridge, for example. Also, in some embodiments some or all of the functionality of I/O interface830, such as an interface to system memory820, may be incorporated directly into processor810.

Network interface840may be configured to allow data to be exchanged between computing device800and other device or devices860attached to a network or networks850, such as other computer systems or devices, for example. In various embodiments, network interface840may support communication via any suitable wired or wireless general data networks, such as types of Ethernet networks, for example. Additionally, network interface840may support communication via telecommunications/telephony networks such as analog voice networks or digital fiber communications networks, via storage area networks such as Fibre Channel SANs (storage area networks) or via any other suitable type of network and/or protocol.

A compute node, which may be referred to also as a computing node, may be implemented on a wide variety of computing environments, such as tablet computers, personal computers, smartphones, game consoles, commodity-hardware computers, virtual machines, web services, computing clusters and computing appliances. Any of these computing devices or environments may, for convenience, be described as compute nodes or as computing nodes.