Red Hat Israel, Ltd.

Ronen Hod

Michael Tsirkin

Paolo Bonzini

Karen Lee Noel

Marcelo Wormsbecker Tosatti

Methods, systems, and computer program products for using a stored interrupt location to provide fast interrupt register access in hypervisors are presented. A computer-implemented method may include maintaining an area of memory in a hypervisor to track a location of an interrupt vector corresponding to an asserted interrupt in a virtual machine, storing the location of the interrupt vector in the area of memory when responding to the asserted interrupt, and examining the area of memory to determine when an interrupt is present in the virtual machine.

Storing interrupt location for fast interrupt register access in hypervisors

A method and system includes calculating a performance metric for each of a plurality of builds of a software application in view of a respective performance test result associated with each of the plurality of builds, calculating a respective difference in performance metrics for each pair of consecutive builds of the plurality of builds, determining a largest performance drop in view of respective differences in the performance metrics among the pairs of consecutive builds of the plurality of builds, wherein the largest performance drop is associated with a first pair of consecutive builds comprising a first build and a second build, determining, by a processing device, a confidence level associated with the largest performance drop in view of performance test results associated with the first build and the second build, in response to determining that the confidence level is greater than or equal to a threshold, identifying one of the first build or the second build as a problematic build of the software application.

Performance regression testing in presence of noise

An application associated with a virtual processor running on a physical processor reads a first value of a counter and a second value of the counter. The counter is indicative of a migration status of the virtual processor with respect to the physical processor. Responsive to determining that the first value of the counter does not equal the second value of the counter, the application ascertains whether a value of a hardware parameter associated with the physical processor has changed during a time interval. The migration status indicates a count of the number of times the virtual processor has migrated a first physical processor to a second physical processor. The application determines the validity of a value of a performance monitoring unit derived from the hardware parameter in view of the application ascertaining whether the value of the hardware parameter has changed during the time interval.

Paravirtualized migration counter for migrating a virtual CPU to a different physical CPU

An application associated with a processor reads a first value of a counter and a second value of the counter. The counter is indicative of a migration status of the application with respect to the processor. Responsive to determining that the first value of the counter does not equal the second value of the counter, the application ascertains whether a value of a hardware parameter associated with the processor has changed during a time interval. The migration status indicates a count of the number of times the application has migrated from one processor to another processor. The application determines the validity of a value of a performance monitoring unit derived from the hardware parameter in view of the application ascertaining whether the value of the hardware parameter has changed during the time interval.

Paravirtualized migration counter

Methods, systems and computer program products for fast interrupt register access in hypervisors are provided. A computer-implemented method may include maintaining a counter associated with a register to track set interrupt vectors in a virtual machine, updating the counter in response to an interrupt event in the virtual machine, and examining the counter to determine when an interrupt vector is set.

Counter for fast interrupt register access in hypervisors

Systems and methods for memory page offloading in multi-processor computer systems. An example method may comprise: detecting, by a computer system, a memory pressure condition on a first node; invalidating a page table entry for a memory page residing on the first node; copying the memory page to a second node; and updating the page table entry for the memory page to reference the second node.

Memory page offloading in multi-node computer systems

An example method for adjusting the rate of transfer of the execution state of a virtual machine undergoing live migration may comprise determining, by a processor, a first rate being a rate of change of an execution state of a virtual machine undergoing live migration from a first computer system to a second computer system. The example method may further comprise determining a second rate being a rate of transfer of the execution state of the virtual machine to the second computer system. The example method may further comprise, responsive to determining that a ratio of the first rate to the second rate exceeds a first threshold ratio, suspending the transfer of the virtual machine execution state to the second computer system.

Reducing or suspending transfer rate of virtual machine migration when dirtying rate exceeds a convergence threshold

A method and system for managing multiple queues providing a communication path between a virtual machine and a hypervisor in a virtual machine system. The multiple queues are bundled together and identified on a polled list. When one of the queues on the polled list is used to communicate a request from the virtual machine to the hypervisor, a virtual machine exit is performed and a virtual machine exit is disabled for all of the queues on the polled list. The queues on the polled list are assigned to an initial host CPU to service requests from the virtual machine. If a particular queue on the polled list experiences a load that exceeds a load threshold, the particular queue is removed from the polled list and assigned to a different host CPU.

Multiple queue management and adaptive CPU matching in a virtual computing system

Systems and methods for adjusting the rate of transmission of the execution state of a virtual machine undergoing live migration. An example method may comprise: determining, by a migration agent executing on a computer system, a first rate being a rate of change of an execution state of a virtual machine undergoing live migration from an origin host computer system to a destination host computer system; determining a second rate being a rate of transferring the execution state of the virtual machine from the origin host computer system to the destination host computer system; determining that a ratio of the first rate to the second rate exceeds a threshold convergence ratio; and reducing the rate of transferring the execution state of the virtual machine from the origin host computer system to the destination host computer system.

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Shoham, Israel

Ronen Hod