Abstract: A method for measuring system performance involves binding a sampling thread to a central processing unit (CPU), starting a soaker thread and binding the soaker thread to the CPU, assigning the soaker thread a lowest priority and scheduling class, placing the soaker thread in a scheduling mechanism based on the lowest priority and scheduling class, and suspending the soaker thread. If a hardware counter is kernel-only, then the following steps are performed: initializing the hardware counters, resuming the soaker thread, and executing the soaker thread if there is no scheduler item of equal or higher priority, where the scheduler item is within the scheduling mechanism.

Abstract: A system for tagged interrupt forwarding comprises a multiprocessor including a first and a second processor, an I/O device, and I/O management software. In response to an application I/O request, the I/O management software may be configured to prepare a request descriptor at the first processor, including an identification of the first processor. The I/O management software may then send a hardware or device-level I/O request to the I/O device. When the I/O device completes the requested hardware I/O operation, it may send a response, which may be received at the second processor. I/O management software at the second processor may be configured to transfer control for processing the response back to the first processor at which the I/O request was initiated, using the tag to identify the first processor. Processing of the response may then be completed at the first processor.

Abstract: A system for tagged interrupt forwarding comprises a multiprocessor including a first and a second processor, an I/O device, and I/O management software. In response to an application I/O request, the I/O management software may be configured to prepare a request descriptor at the first processor, including an identification of the first processor. The I/O management software may then send a hardware or device-level I/O request to the I/O device. When the I/O device completes the requested hardware I/O operation, it may send a response, which may be received at the second processor. I/O management software at the second processor may be configured to transfer control for processing the response back to the first processor at which the I/O request was initiated, using the tag to identify the first processor. Processing of the response may then be completed at the first processor.