Qnx Software Systems Limited

2236008 Ontario Limited

Qnx Software Systems Gmbh & Co. Kg

Cisco Technology, Inc.

Sebastien Marineau-Mes

Peter H Van Der Veen

Dan T Dodge

Brian John Stecher

Colin Burgess

Thomas Fletcher

Attilla Danko

Attila Danko

Pradeep Kumar Kathail

Haresh Kheskani

Hao Zhou

Steve Belair

Srinivas Podila

A system includes a processor and memory storage units storing software code. The software code comprises code for a scheduling system and for generating a plurality of adaptive partitions that are each associated with one or more process threads and that each have a corresponding processor budget. The code also is executable to, when the system is under a normal load, allocate the processor to one of the threads that is in a ready state and has the highest priority among the process threads that are in a ready state. The code is also executable to, when the system is in overload, allocate the processor to one of the process threads that is in a ready state and has the highest priority among the process threads that are in a ready state and for which the adaptive partition that the process thread is associated with has available guaranteed processor budget.

Process scheduler employing adaptive partitioning of process threads

An adaptive partition scheduler is a priority-based scheduler that also provides execution time guarantees (fair-share). Execution time guarantees apply to threads or groups of threads when the system is overloaded. When the system is not overloaded, threads are scheduled based strictly on priority, maintaining strict real-time behavior. When the system is overloaded, threads are scheduled based priority of threads that are in a ready state and based on the available guaranteed processor time budget of the adaptive partition associated with each thread.

Adaptive partitioning for operating system

A system includes a processor, one or more memory storage units, and software code stored in the one or more memory storage units. The software code is executable by the processor to generate a plurality of adaptive partitions that are each associated with one or more process threads. The software code further includes a scheduling system that is executable by the processor for selectively allocating the processor to run the process threads based on a comparison between ordering function values for each adaptive partition. The ordering function value for each adaptive partition is calculated using one or more weighted variables for each adaptive partition. The variables include, for example, 1) the process budget, such as a guaranteed time budget, of the adaptive partition, 2) the critical budget, if any, of the adaptive partition, 3) the rate at which the process threads of an adaptive partition consume processor time.

Process scheduler employing ordering function to schedule threads running in multiple adaptive partitions

A system is set forth that includes a processor, one or more memory storage units, and software code stored in the one or more memory storage units. The software code is executable by the processor to generate a plurality of adaptive partitions that are each associated with one or more process threads. Each of the plurality of adaptive partitions has a corresponding processor budget that is assigned to it. The process threads include a mutex holding thread and a mutex waiting thread. The mutex holding thread is associated with a first adaptive partition and may gain exclusive access to a mutex object. The mutex waiting thread is associated with a second adaptive partition and must wait for access to the mutex object while the mutex object is held by the mutex holding thread. The software code further includes a scheduling system that selectively allocates the processor to run the process threads based, at least in part, on the processor budget of the associated adaptive partitions. The scheduling system bills processor allocation used to run the mutex holding thread to the processor budget of the second adaptive partition when the processor budget of the first adaptive partition has been exhausted.

Process scheduler having multiple adaptive partitions associated with process threads accessing mutexes and the like

A system is set forth comprising a processor and memory storage units storing software code. The software code comprises code for a scheduling system and for generating a plurality of adaptive partitions that are each associated with one or more software threads and that each have a corresponding processor budget. The code also is executable to generate at least one sending thread and at least one receiving thread which responds to communications from the sending thread to execute one or more tasks corresponding to the communications. In operation, the scheduling system selectively allocates the processor to each sending and receiving thread based on the processor budget of the adaptive partition associated with the respective thread. The scheduling system bills the processor budget of the adaptive partition associated with the sending thread for processor allocation used by the receiving thread to respond to communications sent by the sending thread.

An adaptive partition scheduler is a priority-based scheduler that also provides execution time guarantees (fair-share). Execution time guarantees apply to threads or groups of threads when the system is overloaded. When the system is not overloaded, threads are scheduled based strictly on priority, maintaining strict real-time behavior. Even when overloaded, the scheduler provides real-time guarantees to a set of critical threads, as specified by the system architect.

A system includes a processor, one or more memory storage units, and software code stored in the memory storage units. The software code is executable by the processor to generate a plurality of adaptive partitions that are each associated with one or more process threads. Each of adaptive partition has one or more corresponding assigned scheduling attributes. The software code includes a scheduling system for selectively allocating the processor to run process threads based on a comparison between ordering function values for each adaptive partition. Ordering function values are calculated based on scheduling attributes of the corresponding adaptive partition. A critical ordering function value also may be calculated and used to determine the proper manner of billing an associated adaptive partition for the processor allocation used to run its associated critical threads. Methods of implementing various aspects of such a system are also set forth.

A system is set forth that includes a processor, one or more memory storage units, and software code stored in the one or more memory storage units. The software code is executable by the processor to generate a plurality of adaptive partitions that are each associated with one or more process threads. Each of the plurality of adaptive partitions has a corresponding processor time budget. One or more of the process threads are designated as critical threads. Each adaptive partition associated with a critical thread is assigned a corresponding critical time budget. The software code also includes a scheduling system that is executable by the processor for selectively allocating the processor to run the process threads based, at least in part, on the processor time budgets of the respective adaptive partitions. The scheduling system may allocate the processor to run a critical thread based on the available critical time budget of the associated adaptive partition even when the processor time budget of the associated adaptive partition has been exhausted. In one example, the scheduling system functions so that it only bills the critical time budget of an adaptive partition for time used to run an associated critical thread when the processor is overloaded and the critical time budget for the adaptive partition is concurrently exhausted. Methods of implementing such a system are also set forth.

Process scheduler employing adaptive partitioning of critical process threads

An asynchronous message passing mechanism that allows for multiple messages to be batched for delivery between processes, while allowing for full memory protection during data transfers and a lockless mechanism for speeding up queue operation and queuing and delivering messages simultaneously.

Fast and memory protected asynchronous message scheme in a multi-process and multi-thread environment

An operating system architecture and method which provides for transparent inheritance of memory management policies in data processing systems and enhanced memory management is disclosed. The operating system provides for a special 'debug' process flag to be associated with debug and device management processes. When a source process transmits a message to a destination process, the operating system determines whether the source process is a debug process (i.e., whether the source process contains a debug process flag indicator associated therewith). If the source process is a debug process, a debug process flag indicator is also associated with the destination process. The operating system also reserves a portion of the device's memory (a reserve memory pool) which is only allocated to special 'debug' process when the non-reserved pool of memory is depleted.

Growing community of inventors

Ottawa, Canada

Sebastien Marineau-Mes