International Business Machines Corporation

Evelyn Tingmay Yeung

Anil Kalavakolanu

Brian W Hart

Vishal Chittranjan Aslot

James Anthony Pafumi

Minh Q Pham

Vani D Ramagiri

Liang J Jiang

Teresa Hong Pham

Uma S Atluri

Shannon D Moore

Robert E Wallis

Douglas J Griffith

Sreenivas Makineedi

Srinivasa Rao Muppala

Emmanuelle Samir Hanna Matta

Threads of a multithreaded application may be scheduled to different cores and executed in various orders and at various frequencies. Controlling how the threads are scheduled and clock rates of processor cores enables testing multiple possible execution scenarios, which may force previously unknown timing window problems to occur. These timing window problems may then be detected.

Method and technique to find timing window problems

A method, system, and program product is provided for reducing redundant validations for live operating system migration. A control point caches at least one validation inventory that is associated with a logical partition (LPAR). The control point sends the cached validation inventory to a virtualization manager upon an activation of the LPAR associated with the validation inventory. The control point invalidates the cached validation inventory upon notification from the virtualization manager that the validation inventory is changed and is no longer valid. The control point re-validates the validation inventory.

Reducing redundant validations for live operating system migration

Multipath I/O in a computer system includes: receiving asynchronously, for a single I/O operation by a memory controller from a plurality of I/O adapters, a request to access a memory page, where each request to access the memory page includes an adapter-specific tag; and for each request received by the memory controller: determining, by the memory controller, whether an adapter-specific tag has been assigned to the memory page; if an adapter-specific tag has not been assigned to the memory page: assigning, by the memory controller, the received adapter-specific tag to the memory page; and allowing, by the memory controller, access to the memory page; and if an adapter-specific tag has been assigned to the memory page, granting access to the memory page only when the received adapter-specific tag is the adapter-specific tag assigned to the memory page.

Multipath I/O in a computer system

The present disclosure includes a method for migration of a first virtual function of a first device located on a PCI bus and accessible by a device driver using a virtual address. A second virtual function is created on a second device. A base address is determined for the second virtual function as a function of a logical location of the second device within the PCI structure. An offset is determined for the second virtual function as a function of the base address and the virtual address. The device driver is notified that the first virtual function is on hold. The offset is stored in a translation table. The device driver is notified that the hold has been lifted. Accesses to the virtual address and by the device driver to memory of the second virtual function are routed based upon the offset in the translation table.

Function transfer using virtualized mapping

Provided are techniques for the tracing of computer processes and, more specifically, to techniques that enable a work unit to be traced across multiple processing components. A data structure is created and associated with a work unit. The first time a unit of work is processed a tracing context is retrieved form a pool and associated with the data structure. As the unit of work is passed from component to component, the data structure is passed so that each component has access and is able to augment the same tracing context associated with the unit of work.

Capturing multi-component trace for unit of work

In a method for managing resources in a virtualized computing environment, a command to initiate execution of an operating system image dump process for a logical partition of the virtualized computing environment is received while the logical partition is in a process of terminating. One or more resources that are allocated to the logical partition that will not be utilized by the logical partition during execution of the operating system image dump process are determined. A notification to a hypervisor program in the virtualized computing environment is sent. The notification identifies the one or more resources. One of the one or more resources is reallocated. The operating system image dump process is executed.

Resource management in a virtualized environment

A method, system, and computer program product for fast cancellation of an I/O request in a data processing system are provided in the illustrative embodiments. A first component in a stack comprising a plurality of components determines whether a memory buffer associated with the I/O request is valid, the memory buffer being an addressable area in a memory in the data processing system. The first component, responsive to the memory buffer being valid, creates a first request data structure corresponding to the I/O request, wherein the first request data structure includes a reference to the memory buffer. The first component passes the first request data structure to a second component in the stack.

Growing community of inventors

Round Rock, TX, United States of America

Evelyn Tingmay Yeung