Red Hat, Inc.

Ingo Molnar

Thomas Gleixner

Ulrich Drepper

Arnaldo Carvalho De Melo

A system for obtaining performance data for different performance events includes a first application monitoring performance of a second application executing on a computing system. The first application identifies the type of event to be measured with respect to the second application, issues a first system call identifying the type of event, receives an identifier corresponding to the event type, and causes the second application to begin execution. After the execution of the second application is completed, the first application issues a second system call including the identifier corresponding to the event type, and receives a value of a hardware counter corresponding to the event type from an operating system.

Obtaining application performance data for different performance events via a unified channel

Embodiments relate generally to a method of managing asynchronous system calls. The method includes instantiating an asynchronous data structure in a user space and passing the asynchronous data structure to the kernel for execution as an asynchronous system call. The method also includes executing the asynchronous system call in the kernel and returning the kernel to the space in response to the asynchronous system call being blocked on a thread. The method further includes returning a result of the asynchronous system call on the thread in the user space in response to the asynchronous system call being completed.

Asynchronous system calls

A system for providing performance statistics of applications in real time includes a first application that obtains current performance data of at least one second application in real time, utilizes the current performance data to determine a list of functions and the number of events occurred during the execution of each function, presents the resulting data to a user, and periodically refreshes the presented data using up-to-date performance data of the second application.

Profiling the system providing performance statistics in real time

A system for providing performance counter inheritance includes an operating system that receives a request of a first application to monitor performance of a second application, the request identifying an event to monitor during the execution of a task associated with the second application. The operating system causes a task counter corresponding to the event to be activated, and automatically activates a child task counter for each child task upon receiving a notification that execution of a corresponding child task is starting. Further, the operating system adds a value of each child task counter to a value of the task counter to determine a total counter value for the task, and provides the total counter value of the task to the first application.

Performance counter inheritance

Systems and methods of managing primitives are disclosed. A data structure that is stored in user space is registered, wherein the data structure tracks a user controllable mutual exclusion primitive that is acquired by a process running in the user space, and wherein the user controllable mutual exclusion primitive serves as a lock on a resource provided by a computer system. A termination of the process is detected, wherein the process maintains the lock on the resource after termination and the data structure is searched to identify the user controllable mutual exclusion primitive that is acquired by the process that terminated. The user controllable mutual exclusion primitive is released if the user controllable mutual exclusion primitive is identified as being acquired by the process.

Method and system for robust futexes

Embedded protocol objects. Dynamic and static protocol objects are mixed together at a server and included in a dynamic reply to a communication request made by a client application. In effect, static protocol objects can be embedded in dynamic replies, along with dynamic protocol objects. When a request is made by a client to receive a reply, such as a Web page using the HTTP application protocol, the server creates at least one dynamic protocol object to form at least a portion of the reply. The dynamic protocol object or objects are sent to the client application. Static protocol objects are then retrieved and sent to the client application to complete the reply to the application protocol request at the client application.

Embedded protocol objects

A system for handling performance counters and events includes an operating system that receives a request of a first application for performance data associated with a type of event to be performed by a second application, causes a hardware counter pertaining to the event type to be activated, and provides a file descriptor corresponding to the hardware counter to the first application. The operating system then receives a second request of the first application for a value of the hardware counter, where the second request includes the file descriptor, and provides the value of the hardware counter to the first application.

Kernel subsystem for handling performance counters and events

A system for providing software performance counters includes an operating system that receives a first request of a first application to monitor performance of a second application, the first request identifying a type of event to monitor during the execution of the second application. The operating system determines that the event is a software event, monitors the performance of the second application with respect to the type of the software event, and updates a counter associated with the type of the software event based on the monitoring. Further, the operating system receives a second request of the first application for performance data associated with the type of the software event counter, and provides the value of the counter to the first application.

Software performance counters

An embodiment relates generally to a method of preventing resource access conflicts in a software component. The method includes intercepting a lock operation in the software component and testing an associated lock type of the lock operation against a set of rules. The method also includes determining an action based on the associated lock type conflicting one of the rules of the set of rules.

Method and system for a kernel lock validator

An embodiment relates to a method of managing primitives. The method includes providing a data structure available in user-space where the data structure comprises at least one futex. The method also includes detecting a termination of the process and searching the data structure for status of the at least one futex. The method further includes releasing the at least one futex in response to status of the at least one futex being held and setting a flag for at least one futex. The method further includes notifying at least one process waiting for the released at least one futex.

Method and apparatus for atomic file look-up. An atomic look-up operation allows an application to find out whether a file is opened atomically based on whether or not the file path is present in a file system namespace cache. If not, the file open request can be redirected, avoiding or minimizing impacts to the scheduling of various operations involved in executing an application. The request can be redirected by the application to a process that includes blocking point handling. An operating system according to the present invention includes a file system including a file system namespace, and an operating system kernel is operatively connected to the file system. The operating system kernel includes the file system namespace cache and the atomic look-up operation.

Method and apparatus for atomic file look-up

Method and apparatus for handling communication requests at a server without context switching. An application protocol subsystem and protocol modules are disposed within an operating system kernel at a server. The protocol subsystem creates an 'in-kernel' protocol stack that stores information regarding application protocol requests, such as HTTP and FTP requests, in a kernel request structure. A user space application can then continue execution while the operating system responds to the application protocol request without context switching. In this way, application protocol requests received over a network are handled and responded to by the server without causing a context switch.

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Kagel, Germany

Ingo Molnar