Input/output decoupling system method having a cache for exchanging data between non-volatile storage and plurality of clients having asynchronous transfers

• US 7,640,381 B1
• Filed: 01/04/2006
• Issued: 12/29/2009
• Est. Priority Date: 10/07/2005
• Status: Active Grant

• Current Assignee: Intellectual Ventures I LLC (Intellectual Ventures LLC)
• Original Assignee: Software Site Application Limited Liability Company
• Inventors: Zhang, Ji, Liu, Hain-Ching, Ding, Jian Gang
• Primary Examiner(s): PEYTON, TAMMARA R
• Application Number:
  US11/325,970
• Time in Patent Office: 1,455 Days
• Field of Search: 710/56, 710/5, 710/52, 711/141, 711/151
• US Class Current: 710/56
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An I/O decoupling system comprising an I/O accelerator coupled between a host interface and a channel interface, wherein the I/O accelerator comprises a host manager, a buffer manager a function manager, and a disk buffer. The host manager is coupled to the host interface to receive a request from a connected host computer. The function manager in response to receiving the request allocates the disk buffer and determines a threshold offset for the buffer while coordinating the movement of data to the disk buffer through the channel interface coupled to the disk buffer.

Claims

1. An apparatus, comprising:

a storage interface configured to communicate with a storage system having a non-volatile storage component;

a host interface configured to communicate with a plurality of clients;

a cache configured to cache communications exchanged between the non-volatile storage component and the plurality of clients, the cache configured to associate buffers with the plurality of clients; and

circuitry configured to;

identify a data rate for transferring data from the apparatus, over the host interface, to one of the plurality of clients, wherein the identified data rate is based on an amount of data cached in the buffer for the receiving client and decoupled from asynchronous transfers over the storage interface; and

stream the cached data to the receiving client according to the identified data rate that is decoupled from the asynchronous transfers.

2. The apparatus of claim 1, wherein the circuitry is further configured to:

detect expected disruption of a data transfer over the host interface based on monitoring the cache;

re-prioritize asynchronous data transfers over the storage interface in response to detecting expected disruption of the data transfer, the re-prioritization causing a current asynchronous data transfer from the non-volatile storage component to be halted in order to process a different asynchronous data transfer from the non-volatile storage component; and

maintain a transfer priority established by the re-prioritization until a new expected data transfer disruption is detected;

wherein the halted asynchronous data transfer is not resumed until an expected disruption of a data transfer associated with the halted asynchronous data transfer occurs.

3. The apparatus of claim 2, wherein the processed asynchronous transfer is continued subsequent to resolution of the detected expected disruption and independently of a history of priority between the asynchronous data transfers.

4. The apparatus of claim 1, wherein the plurality of clients are a plurality of software applications operating on host computers that are coupled to the host interface.

5. The apparatus of claim 1, wherein the host interface includes a network interface.

6. The apparatus of claim 1, wherein the storage interface is configurable for communicating with a Redundant Array of Inexpensive Disks (RAID) controller.

7. The apparatus of claim 1, wherein data in the data transfer over the host interface is formatted according to a first block size that is smaller than a second block size of the asynchronous transfers.

8. The apparatus of claim 1, wherein the circuitry is configured to reformat asynchronously received data into a different block size for transmission over the host interface.

9. The apparatus of claim 1, wherein the cache comprises volatile memory.

10. The apparatus of claim 1, wherein the non-volatile storage is initialized by a file system, the initialization allocating fixed data blocks each having a first size on the non-volatile storage and mapping the allocated fixed data blocks to the file system, and wherein the first size of each fixed data block is larger than a second size of a file to be requested by an application;

and

wherein the circuitry is further configured to;

transfer a block of data containing the file from the non-volatile storage over the storage interface to cache the block of data, the transferred block of data being of the first size and containing the file to be requested and other data including at least a portion of another file;

parse data from the block into a plurality of smaller blocks and store the plurality of smaller blocks on the cache in one of the buffers associated with the application;

in response to a request from the application for the file, access only a subset of the smaller blocks and transfer data from the accessed smaller blocks to one of the clients that is associated with the application, wherein data from a remaining one of the smaller blocks is not transferred to the associated client in response to the request for the file.

11. The apparatus of claim 1, wherein the host interface is configured to connect to an I/O port of a personal computer, server, or workstation.

12. The apparatus of claim 11, wherein the storage interface is configured to connect to an I/O port of a disk-based storage device.

13. The apparatus of claim 1, wherein the data stored on the non-volatile storage component is formatted using a first block size format that maps to a file system on at least one of the clients, wherein the circuitry is further configured to align data stored in the cache according to communications exchanged with the plurality of clients such that the data stored in the cache is organized according to a second block size format that is different than the first block size format.

14. The apparatus of claim 1, wherein the identified data rate is an isochronous data rate, and wherein the apparatus proxies isochronous data rate identification for the storage system and frees the storage system from having to provide isochronous data transfers.

15. An apparatus, comprising:

a storage interface configured to communicate with a storage component;

a host interface configured to communicate with a plurality of clients;

a buffering component configured to buffer communications exchanged between the storage component and the plurality of clients, the buffering component configured to associate buffers with the plurality of clients; and

circuitry configured to;

identify a data rate for transferring data from the apparatus, over the host interface, to one of the plurality of clients, wherein the identified data rate is based on an amount of data existing in the buffer for the receiving client and decoupled from asynchronous transfers over the storage interface; and

stream the buffered data to the receiving client according to the identified data rate that is decoupled from the asynchronous transfers;

wherein the circuitry is further configured to align data stored in the buffering component according to communications exchanged with the plurality of clients such that the data stored in the buffering component is organized according to a first block size format that is different than a second block size format used for organizing the data stored on the storage component.

16. The apparatus of claim 15, wherein the storage component comprises non-volatile memory and the buffering component comprises volatile memory.

17. The apparatus of claim 15, wherein the identified data rate is an isochronous data rate, and wherein the apparatus proxies isochronous data rate identification for the storage system and frees the storage system from having to provide isochronous data transfers.

18. An apparatus, comprising:

means for communicating with a storage system having a non-volatile storage component;

means for communicating with a client and providing the client access through the apparatus to data stored on the non-volatile storage component;

means for selecting a data rate for transferring data from the apparatus, over the client communication means, to the client, wherein the selected data rate is based on an amount of data cached on the apparatus and decoupled from asynchronous transfers over the non-volatile storage component communication means; and

means for transferring the cached data to the client according to the selected data rate.

19. The apparatus of claim 18, further comprising:

means for detecting expected disruption of a data transfer between the apparatus and the client;

means for re-prioritizing asynchronous data transfers between the apparatus and the non-volatile storage component in response to detecting expected disruption of the data transfer; and

means for maintaining a transfer priority established by the re-prioritization until a new expected data transfer disruption is detected;

wherein the apparatus is configured to continue an asynchronous transfer selected according to the re-prioritization until completion unless a new re-prioritization occurs according to the detection means.

20. The apparatus of claim 19, further comprising:

means for storing the asynchronous data transfers in buffers associated with host computers coupled to the client communication means;

means for monitoring depletion of the buffers; and

means for detecting the expected disruptions according to the monitoring means.

21. The apparatus of claim 20, further comprising:

means for identifying transfer rates of the host computers;

means for controlling data transfers over the client communication means according to the identified transfer rates;

means for establishing interrupt thresholds for each buffer according to the identified transfer rates and buffer size; and

means for monitoring buffer depletion according to the established interrupt thresholds.

22. The apparatus of claim 18, further comprising:

means for identifying transfer rates of host computers coupled to the client communication means; and

means for controlling is data rate selection according to the identified transfer rates.

23. The apparatus of claim 18, further comprising a volatile memory to cache at least a portion of the data stored on the non-volatile memory component.

24. The apparatus of claim 18, wherein the identified data rate is an isochronous data rate, and wherein the apparatus proxies isochronous data rate identification for the storage system and frees the storage system from having to provide isochronous data transfers.

25. An apparatus, comprising:

a storage interface configured to communicate with a storage system having a non-volatile storage component;

a host interface configured to communicate with a plurality of clients;

a cache configured to cache communications exchanged between the non-volatile storage component and the plurality of clients, the cache configured to associate a buffer with each client; and

circuitry configured to;

identify a data rate for transferring data from the apparatus, over the host interface, to one of the plurality of clients, wherein the identified data rate is based on an amount of data existing in the buffer for the receiving client and decoupled from asynchronous transfers over the storage interface.

26. The apparatus of claim 25, wherein the circuitry is further configured to:

transfer data over the host interface between the plurality of clients and their associated buffers;

monitor buffer capacity to detect when one of the data transfers over the host interface is expected to deplete a respective one of the buffers such that the determined data rate from that detected buffer is expected to be disrupted;

halt a current asynchronous data transfer from the non-volatile storage component to one of the non-detected buffers in response to the detection;

process an asynchronous data transfer from the non-volatile storage component to the detected buffer to prevent disruption of the determined data rate, and continue to monitor the other non-detected buffers during the processing; and

continue the processed asynchronous data transfer until the continued monitoring detects a different buffer;

wherein the processed asynchronous data transfer is continued independently of resolving the expected depletion as long as no other buffers corresponding to the non-volatile storage component are detected.

27. The apparatus of claim 26, wherein the processed asynchronous data transfer is continued until the earlier of completion or detection of another buffer associated with the non-volatile storage component to maximize a continuous burst read from a disk in the non-volatile storage component.

28. The apparatus of claim 27, wherein the continuation of the processed asynchronous data transfer continues without halting unless a new detection occurs thereby eliminating a seek penalty.

29. The apparatus of claim 26, wherein the circuitry is configured to delay resumption of the halted asynchronous data transfer until detecting expected disruption of a data transfer from the buffer associated with the halted asynchronous data transfer.

30. The apparatus of claim 26, wherein the non-volatile storage component is disk-based, and wherein a delay in resuming of the halted asynchronous data transfer avoids thrashing between disk locations.

31. The apparatus of claim 25, wherein the plurality of clients are software programs operating on a host computer.

32. The apparatus of claim 25, wherein information is formatted on the buffers independently of a formatting of the non-volatile storage component.

33. The apparatus of claim 25, wherein the cache comprises volatile memory.

34. The apparatus of claim 25, wherein the identified data rate is an isochronous data rate, and wherein the apparatus proxies isochronous data rate identification for the storage system and frees the storage system from having to provide isochronous data transfers.