Abstract: In a computer system, a method of controls interrupts which correspond to input/output (I/O) processing. For each delivery of an I/O completion interrupt, the method provides a recordation of a delivery time; identifies I/O completions for which deliveries of corresponding I/O completion interrupts involve deliveries of inter-processor interrupts; and for each of the identified I/O completions, accesses the recordation of the most recent delivery time to determine whether a selected period of time has elapsed since a last delivery of an inter-processor interrupt. As a response to a determination that the selected period has elapsed, an inter-processor interrupt is delivers. As a response to a determination that less than the duration of the selected period has elapsed, the method refrains from delivering an inter-processor interrupt.

Abstract: Completion interrupts corresponding to I/O requests issued by a virtual machine guest, which runs on a host platform, are virtualized in such a way that I/O completion interrupts to the requesting guest are delivered no faster than it can stably handle them, but, when possible, faster than the nominal speed of a virtual device to which a virtual machine addresses the I/O request. In general, completion events received from the host platform in response to guest I/O requests are examined with respect to time. If enough time has passed that the virtual device would normally have completed the I/O request, then the completion interrupt is delivered to the guest. If the nominal time has not elapsed, however, the invention enqueues and time-stamps the event and delivers it at the earliest of a) the normal maturity time, or b) at a safepoint.

Abstract: In a computer system, a method of controlling coalescence of interrupts includes dynamically basing a current level of interrupt coalescing upon a determination of outstanding input/output (I/O) commands for which corresponding I/O completions have not been received. Deliveries of interrupts are executed on the basis of the current level and in an absence of enabling timing-triggered delivery of an interrupt.

Abstract: In a virtual machine, swap activities of a hypervisor and a guest OS are reconciled so that redundant input-output operations (IOs) can be avoided and a synchronous response time of the virtual machine improved. This is achieved with a map of memory pages to blocks of storage. For a write IO to write contents of a memory page into a target block, the map is examined to see if it contains a valid entry for the memory page. If the map contains the valid entry, the write IO is prevented from being issued and a data structure is updated so that subsequent IOs to the target block is redirected from the target block to a block that is associated with the physical memory page in the valid entry. On the other hand, if the map does not contain the valid entry, the write IO is issued.

Abstract: Computer implemented methods, computer program products and computer systems synchronize copies of a virtual disk. A record of blocks that are modified during an access session of a copy of the virtual disk is maintained. For each partition of the virtual disk, a file system level indication of currently relevant blocks is obtained. Only those blocks that were modified during the access session and are currently relevant are copied to at least one additional copy of the virtual disk.

Abstract: Completion interrupts corresponding to I/O requests issued by a virtual machine guest, which runs on a host platform, are virtualized in such a way that I/O completion interrupts to the requesting guest are delivered no faster than it can stably handle them, but, when possible, faster than the nominal speed of a virtual device to which a virtual machine addresses the I/O request. In general, completion events received from the host platform in response to guest I/O requests are examined with respect to time. If enough time has passed that the virtual device would normally have completed the I/O request, then the completion interrupt is delivered to the guest. If the nominal time has not elapsed, however, the invention enqueues and time-stamps the event and delivers it at the earliest of a) the normal maturity time, or b) at a safepoint.

Abstract: Completion interrupts corresponding to I/O requests issued by a virtual machine guest, which runs on a host platform, are virtualized in such a way that I/O completion interrupts to the requesting guest are delivered no faster than it can stably handle them, but, when possible, faster than the nominal speed of a virtual device to which a virtual machine addresses the I/O request. In general, completion events received from the host platform in response to guest I/O requests are examined with respect to time. If enough time has passed that the virtual device would normally have completed the I/O request, then the completion interrupt is delivered to the guest. If the nominal time has not elapsed, however, the invention enqueues and time-stamps the event and delivers it at the earliest of a) the normal maturity time, or b) at a safepoint.

Abstract: In a computer system, a method of controlling coalescence of interrupts includes dynamically basing a current level of interrupt coalescing upon a determination of outstanding input/output (I/O) commands for which corresponding I/O completions have not been received. Deliveries of interrupts are executed on the basis of the current level and in an absence of enabling timing-triggered delivery of an interrupt.

Abstract: Computer implemented methods, computer program products and computer systems synchronize copies of a virtual disk. A record of blocks that are modified during an access session of a copy of the virtual disk is maintained. For each partition of the virtual disk, a file system level indication of currently relevant blocks is obtained. Only those blocks that were modified during the access session and are currently relevant are copied to at least one additional copy of the virtual disk.