Abstract: An embodiment of monitoring resource usage in a computing environment begins with a first client registering a session with a monitoring entity. The session comprises an event type, a count, a start condition, an end condition, and a sample type. Next, a second client registers with the session. Upon occurrence of the start condition and until occurrence of the end condition or until interrupted, the monitoring entity iteratively initiates a counting of occurrences of the event type that continues until reaching the count and saves a sample according to the sample type upon reaching the count. The resource monitoring entity provides at least a portion of a plurality of samples to the first client.

Abstract: According to an embodiment, a method of sampling hardware events in a computer system comprises a first step and iterative performance of second and third steps. In the first step, an initiator virtual machine identifies a profiling event and a count to a virtual machine monitor. The virtual machine monitor iteratively performs the second and third steps. In the second step, the virtual machine monitor programs a hardware event counter with the count for the profiling event. In the third step, upon receiving an interrupt from the hardware event counter, the virtual machine monitor saves a sample that comprises a code-in-execution identifier.

Abstract: An embodiment of a method of virtualizing a counter in a computer system comprises a first step and iterative performance of second through fifth steps. In the first step, a virtual machine monitor programs a hardware event counter with an initial count for a profiling event for a virtual machine. In the second step, the virtual machine monitor saves a suspension count and disables the hardware event counter upon suspending operation of the virtual machine. In the third step, the virtual machine monitor programs the hardware event counter with the suspension count upon resuming the operation of the virtual machine. Upon receiving an interrupt from the hardware event counter that provides notification of reaching the initial count, the virtual machine monitor performs the fourth and fifth steps. In the fourth step, the virtual machine monitor saves a sample that comprises an event identifier and a code-in-execution indicator.

Abstract: An embodiment of a method of restoring a communication state of a process includes creating a new socket for a socket saved as part of a checkpoint of the communication state. The new socket is initialized with an adjusted transmission control protocol state saved as part of the checkpoint. The adjusted transmission control protocol state indicates that a send buffer and a receive buffer are empty. Send data saved as part of the checkpoint is written into the new socket. Receive data saved as part of the checkpoint is written into a restart buffer. While at least a portion of the receive data remains in the restart buffer, a socket read system call for the new socket is redirected to read the receive data that remains in the restart buffer.

Abstract: An embodiment of a method of performing a kernel level task upon initial execution of a child process at a user level begins with setting an instruction pointer for an initial child process instruction to an instruction to enter a kernel level. The method continues with beginning the child process which places a return value in a register for the child process and which causes the child process to enter the kernel level. The method concludes with executing a system call having a system call number of the return value. The system call comprises the kernel level task.

Abstract: An embodiment of a method of checkpointing parallel processes in execution within a plurality of process domains begins with a step of setting communication rules to stop communication between the process domains. Each process domain comprises an execution environment at a user level for at least one of the parallel processes. The method continues with a step of checkpointing each process domain and any in-transit messages. The method concludes with a step of resetting the communication rules to allow the communication between the process domains.

Abstract: A method of checkpointing and restarting processes that share a file that is open begins with a step of assigning a priority to one of the processes that share the file. This identifies a priority process. The method concludes with a step of reopening the file when restoring the priority process.

Abstract: A method of restoring processes within a process domain begins with a step of restoring a tree of processes in which at least two of the processes share at least a resource. The method continues with a step of restoring a checkpoint state of each resource used by the processes after a time when a possible need for a restoration state of the resource exists. According to an embodiment, the restoration state comprises information used by the method during the step of restoring the tree of processes. According to another embodiment, the restoration state comprises information used by the method during the step of restoring the checkpoint state of one or more particular resources. The method concludes with a step of resuming execution of each process after restoration of the checkpoint state of the resources used by the process.

Abstract: An embodiment of a method of checkpointing a virtual memory for a process comprises: accessing a page table that correlates logical addresses for the process to physical locations; saving memory resident pages identified for the process from the page table; and saving disk swap pages identified for the process from the page table, the step of saving disk swap pages being performed after the step of saving the memory resident pages.

Abstract: A method and system thereof for reducing the energy consumed when decoding an encoded and synchronized multimedia data stream, wherein the data stream is non-preemptable and subject to precedence constraints. In a client-server environment, the server delivers to the client the stream for decoding. The client has a processor operating on a discrete variable-voltage power supply. Prior to transmitting the stream to the client, the server produces an execution schedule according to the precedence constraints. The server also assigns a voltage setting for each task in the schedule, wherein each task decodes a frame in the stream without preemption. The server transmits the execution schedule and voltage settings to the client with the encoded data stream. The schedule and voltage settings reduce energy consumption by the client while satisfying multimedia timing constraints.

Abstract: A method and system thereof for reducing the energy consumed when decoding an encoded and synchronized multimedia data stream, wherein the data stream is non-preemptable and subject to precedence constraints. In a client-server environment, the server delivers to the client the stream for decoding. The client has a processor operating on a discrete variable-voltage power supply. Prior to transmitting the stream to the client, the server produces an execution schedule according to the precedence constraints. The server also assigns a voltage setting for each task in the schedule, wherein each task decodes a frame in the stream without preemption. The server transmits the execution schedule and voltage settings to the client with the encoded data stream. The schedule and voltage settings reduce energy consumption by the client while satisfying multimedia timing constraints.