Patent application number | Description | Published |
20110088030 | Efficient Virtualization of Input/Output Completions for a Virtual Device - 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. | 04-14-2011 |
20110289345 | METHOD AND SYSTEM FOR ENABLING CHECKPOINTING FAULT TOLERANCE ACROSS REMOTE VIRTUAL MACHINES - A checkpointing fault tolerance network architecture enables a backup computer system to be remotely located from a primary computer system. An intermediary computer system is situated between the primary computer system and the backup computer system to manage the transmission of checkpoint information to the backup VM in an efficient manner. The intermediary computer system is networked to the primary VM through a high bandwidth connection but is networked to the backup VM through a lower bandwidth connection. The intermediary computer system identifies updated data corresponding to memory pages that have been least recently modified by the primary VM and transmits such updated data to the backup VM through the low bandwidth connection. In such manner, the intermediary computer system economizes the bandwidth capacity of the low bandwidth connection, holding back updated data corresponding to more recently modified memory pages, since such memory pages may be more likely to be updated again in the future. | 11-24-2011 |
20120030407 | SYSTEM AND METHOD FOR IMPROVING MEMORY LOCALITY OF VIRTUAL MACHINES - A system and related method of operation for migrating the memory of a virtual machine from one NUMA node to another. Once the VM is migrated to a new node, migration of memory pages is performed while giving priority to the most utilized pages, so that access to these pages becomes local as soon as possible. Various heuristics are described to enable different implementations for different situations or scenarios. | 02-02-2012 |
20120204061 | METHOD AND SYSTEM FOR ENABLING CHECKPOINTING FAULT TOLERANCE ACROSS REMOTE VIRTUAL MACHINES - A checkpointing fault tolerance network architecture enables a backup computer system to be remotely located from a primary computer system. An intermediary computer system is situated between the primary computer system and the backup computer system to manage the transmission of checkpoint information to the backup VM in an efficient manner. The intermediary computer system is networked to the primary VM through a first connection and is networked to the backup VM through a second connection. The intermediary computer system identifies updated data corresponding to memory pages that have been least recently modified by the primary VM and transmits such updated data to the backup VM through the first connection. In such manner, the intermediary computer system holds back updated data corresponding to more recently modified memory pages, since such memory pages may be more likely to be updated again in the future. | 08-09-2012 |
20120265963 | LARGE-PAGE OPTIMIZATION IN VIRTUAL MEMORY PAGING SYSTEMS - A computer system that is programmed with virtual memory accesses to physical memory employs multi-bit counters associated with its page table entries. When a page walker visits a page table entry, the multi-bit counter associated with that page table entry is incremented by one. The computer operating system uses the counts in the multi-bit counters of different page table entries to determine where large pages can be deployed effectively. In a virtualized computer system having a nested paging system, multi-bit counters associated with both its primary page table entries and its nested page table entries are used. These multi-bit counters are incremented during nested page walks. Subsequently, the guest operating systems and the virtual machine monitors use the counts in the appropriate multi-bit counters to determine where large pages can be deployed effectively. | 10-18-2012 |
20130067135 | SYSTEM AND METHOD FOR IMPROVING MEMORY LOCALITY OF VIRTUAL MACHINES - A system and related method of operation for migrating the memory of a virtual machine from one NUMA node to another. Once the VM is migrated to a new node, migration of memory pages is performed while giving priority to the most utilized pages, so that access to these pages becomes local as soon as possible. Various heuristics are described to enable different implementations for different situations or scenarios. | 03-14-2013 |
20130159635 | SYSTEM AND METHOD FOR MAINTAINING MEMORY PAGE SHARING IN A VIRTUAL ENVIRONMENT - In a virtualized system using memory page sharing, a method is provided for maintaining sharing when Guest code attempts to write to the shared memory. In one embodiment, virtualization logic uses a pattern matcher to recognize and intercept page zeroing code in the Guest OS. When the page zeroing code is about to run against a page that is already zeroed, i.e., contains all zeros, and is being shared, the memory writes in the page zeroing code have no effect. The virtualization logic skips over the writes, providing an appearance that the Guest OS page zeroing code has run to completion but without performing any of the writes that would have caused a loss of page sharing. The pattern matcher can be part of a binary translator that inspects code before it executes. | 06-20-2013 |
20130326518 | Efficient Virtualization of Input/Output Completions for a Virtual Device - 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. | 12-05-2013 |