Systems and Methods for Managing Data Input/Output Operations

• US 20120210043A1
• Filed: 02/15/2011
• Published: 08/16/2012
• Est. Priority Date: 02/15/2011
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: IO Turbine, Inc. (Western Digital Corporation)
• Inventors: Joshi, Vikram, Luan, Yang, Vidwans, Hrishikesh A., Apte, Manish R., Brown, Michael F.
• Granted Patent: US 8,874,823 B2
• Time in Patent Office: Days
• US Class Current: 711/6
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 2009/45579 I/O management, e.g. providing access to device drivers or storage
• CPC Class Codes: G06F 2212/1021 Hit rate improvement
• CPC Class Codes: G06F 2212/452 Instruction code
• CPC Class Codes: G06F 2212/604 Details relating to cache allocation
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

Systems and methods for managing data input/output operations are described. In one aspect, a device driver identifies a data read operation generated by a virtual machine in a virtual environment. The device driver is located in the virtual machine and the data read operation identifies a physical cache address associated with the data requested in the data read operation. A determination is made regarding whether data associated with the data read operation is available in a cache associated with the virtual machine.

Claims

1. A computer-implemented method comprising:

identifying a data read operation generated by a virtual machine in a virtual environment, wherein the data read operation is identified by a device driver within the virtual machine generating the data read operation; and

determining whether data associated with the data read operation is available in a cache associated with the virtual machine.

2. The computer-implemented method of claim 1, further comprising retrieving the data associated with the data read operation from the cache if the cache contains the data associated with the data read operation.

3. The computer-implemented method of claim 1, further comprising identifying a plurality of virtual machines in the virtual environment.

4. The computer-implemented method of claim 1, wherein the device driver is an input/output driver.

5. The computer-implemented method of claim 1, further comprising determining a physical cache address associated with the data requested in the data read operation.

6. The computer-implemented method of claim 1, further comprising translating a storage I/O address associated with the data read operation into physical cache address using a cache tag associated with the storage I/O address.

7. The computer-implemented method of claim 6, wherein the cache tag is stored in the virtual machine.

8. The computer-implemented method of claim 6, wherein the cache tag is associated with a particular page in the cache.

9. A virtualized computing system comprising:

a plurality of virtual machines, wherein each virtual machine includes an input/output driver for intercepting input/output operations associated with the virtual machine;

a shared data cache; and

a cache provisioner coupled to the plurality of virtual machines and the shared data cache, the cache provisioner configured to allocate portions of the shared data cache to virtual machines based on the intercepted input/output operations.

10. The virtualized computing system of claim 9, wherein the shared data cache is a flash memory device.

11. The virtualized computing system of claim 9, wherein the shared data cache is a solid state drive.

12. The virtualized computing system of claim 9, wherein the shared data cache includes volatile memory.

13. The virtualized computing system of claim 9, wherein each of the plurality of virtual machines further includes a cache management system.

14. The virtualized computing system of claim 13, wherein the cache management system includes multiple cache tags that associate storage I/O addresses in the associated virtual machine with physical addresses in the shared data cache.

15. The virtualized computing system of claim 9, wherein the input/output driver further directs intercepted input/output operations to the cache provisioner for processing.

16. The virtualized computing system of claim 9, wherein the cache provisioner is further configured to communicate information regarding allocated cache resources to each of the plurality of virtual machines.

17. The virtualized computing system of claim 9, wherein the cache provisioner is further configured to dynamically provision input/output operation capacity from the cache among the plurality of virtual machines.

18. The virtualized computing system of claim 17, wherein the cache provisioner is further configured to communicate information regarding allocated input/output operation capacity to each of the plurality of virtual machines.

19. The virtualized computing system of claim 9, wherein the cache provisioner is further configured to maintain a listing of valid data stored in the shared data cache.

20. The virtualized computing system of claim 9, further comprising a cache management system configured to identify data candidates for removal from the shared data cache.

21. The virtualized computing system of claim 9, further comprising a cache management having a multi-bit clock timer to identify stored data that has not been recently accessed.

22. The virtualized computing system of claim 9, further comprising a cache management system having a clock timer to identify stored data that has not been recently accessed, wherein the clock timer has a plurality of temporal trigger intervals.

23. The virtualized computing system of claim 9, wherein each of the plurality of virtual machines represents a virtual desktop.

24. The virtualized computing system of claim 9, wherein each of the plurality of virtual machines represents a server application.

25. The virtualized computing system of claim 9, wherein each of the plurality of virtual machines is configured to share the shared data cache without risk of accessing data associated with a different virtual machine.

26. The virtualized computing system of claim 9, further comprising a virtualization kernel configured to manage the operation of the plurality of virtual machines.

27. A computer-implemented method comprising:

allocating a plurality of cache pages to a virtual machine, wherein each cache page has an associated cache tag stored in the virtual machine;

determining a cache hit rate for the virtual machine based on the plurality of allocated cache pages;

allocating additional cache tags to the virtual machine without increasing the cache pages allocated to the virtual machine; and

identifying changes to the cache hit rate for the virtual machine based on the additional allocation of cache tags.

28. The computer-implemented method of claim 27, further comprising increasing the allocation of cache pages to the virtual machine if the cache hit rate increases as a result of the additional allocation of cache tags.

29. The computer-implemented method of claim 27, further comprising identifying a minimum or optimum number of cache tags that provide an improved cache performance for a particular virtual machine.

30. The computer-implemented method of claim 29, further comprising allocating cache pages to the particular virtual machine based on the minimum or optimum number of cache tags that provide an improved cache performance.

31. A data processing system:

a processor; and

a memory coupled to the processor, the memory comprising processor-executable instructions that, when executed by the processor, perform operations including;

identifying a data input/output operation generated by a virtual machine in a virtual environment, wherein the data input/output operation is identified through an input/output driver contained within the virtual machine;

determining whether data associated with the data input/output operation is available in a cache associated with the virtual machine; and

retrieving the data associated with the data input/output operation from the cache if the cache contains the data associated with the data read operation.

32. A computer-implemented method comprising:

identifying a data read operation generated by a base operating system, wherein the data read operation is identified by a device driver within the base operating system generating the data read operation; and

determining whether data associated with the data read operation is available in a cache associated with the base operating system.

33. The computer-implemented method of claim 32, wherein the device driver is an input/output driver.

34. The computer-implemented method of claim 32, further comprising translating a storage I/O address associated with the data read operation into physical cache address using a cache tag associated with the storage I/O address.

35. The computer-implemented method of claim 34, wherein the cache tag is stored in the base operating system.