Dynamically self-adjusting polling mechanism

• US 6,931,460 B2
• Filed: 05/19/2003
• Issued: 08/16/2005
• Est. Priority Date: 05/19/2003
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Emulex Design & Manufacturing Corp. (Broadcom, Inc.)
• Inventors: Barrett, David Michael
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Schneider, Joshua D
• Application Number:
  US10/440,681
• Publication Number:
  US 20040236880A1
• Time in Patent Office: 820 Days
• Field of Search: 710/46, 710/5, 710/6, 710/15, 710/19, 710/52, 710/56, 710/57, 710/53, 370/449
• US Class Current: 710/57
• CPC Class Codes: G06F 11/0745 in an input/output transactions management context input/output processing in general G06F13/00
• CPC Class Codes: G06F 11/0787 Storage of error reports, e.g. persistent data storage, storage using memory protection

Abstract

A system and method is disclosed for preventing the loss of event messages due to message buffer overruns. A fixed vendor-specific buffer pool is loaded with log messages by firmware in an adapter. A service application periodically polls a device driver for messages in the buffer pool. The device driver responds with the number of messages stored in the buffer pool and the total number of buffers in the buffer pool. The service application then issues “get next message” requests to receive the stored messages. Once the buffer pool has been emptied, the service application writes the messages to a disk file. The service application then computes a percent utilization of the buffer pool, and if the percent utilization exceeds a predetermined threshold, an algorithm is employed for increasing the polling frequency. If the percent utilization is below the threshold, an algorithm is employed for decreasing the polling frequency.

Claims

1. A system for storing selected vendor-specific messages generated in an adapter card coupled to a host computer into a disk file controlled by the host computer, comprising:

logic resident on the adapter card for generating the vendor-specific messages and selecting certain types of the vendor-specific messages for logging;

a fixed-size buffer pool in the host computer for receiving and storing the selected vendor-specific messages; and

at least one processor in the host computer programmed for executing a service application in user space in the host computer to periodically poll the buffer pool, retrieve the selected vendor-specific messages from the buffer pool, store the selected vendor-specific messages in the disk file, increase a polling frequency of the buffer pool according to a first methodology if buffer pool utilization is at or above a first predetermined threshold, and decrease the polling frequency of the buffer pool according to a second methodology if the buffer pool utilization is below a second predetermined threshold for a predetermined number of consecutive polling periods to account for multiple bursts of vendor-specific messages occurring within a period of vendor-specific message inactivity.

2. The system as recited in claim 1, the at least one processor further programmed for executing a device driver in kernel space for managing the storing and retrieval of the messages from the buffer pool.

3. The system as recited in claim 2, the at least one processor further programmed for allocating the fixed-sized buffer pool upon initialization of the device driver.

4. The system as recited in claim 2, wherein in response to a poll from the service application in user space, the at least one processor is further programmed for generating a reply to the service application containing a number of messages in the buffer pool and a total number of buffers in the buffer pool.

5. The system as recited in claim 4, the at least one processor further programmed in accordance with the service application for issuing one “

get next messages”

request to the device driver for each message in the buffer pool, and further programmed in accordance with the device driver to transmit and remove one message from the buffer pool for each “

get next message”

request received at the device driver.

6. The system as recited in claim 5, the at least one processor further programmed for storing all messages into the disk file once all messages have been received in user space.

7. The system as recited in claim 4, the at least one processor further programmed for computing the buffer pool utilization by dividing the number of messages in the buffer pool by the total number of buffers in the buffer pool.

8. The system as recited in claim 1, the logic for selecting the vendor-specific messages in accordance with a configurable logging level.

9. The system as recited in claim 1, wherein the adapter card is a host bus adapter (HBA) for managing a transfer of information between the host computer and a storage area network.

10. The system as recited in claim 9, wherein the HBA manages the transfer of information between the host computer and an iSCSI-compatible storage area network.

11. A storage area network (SAN) comprising the system of claim 10, wherein an iSCSI network is coupled to the HBA and one or more storage devices are coupled to the iSCSI network.

12. The system as recited in claim 9, wherein the HBA manages the transfer of information between the host computer and fibre channel-compatible storage area network.

13. A storage area network (SAN) comprising the system of claim 12, wherein a fibre channel network is coupled to the HBA and one or more storage devices are coupled to the fibre channel network.

14. The system as recited in claim 1, the first methodology for increasing a polling frequency of the buffer pool to a predetermined maximum polling rate if the buffer pool utilization is at or above the first predetermined threshold, and maintaining this maximum polling rate until the buffer pool utilization falls below the first predetermined threshold.

15. The system as recited in claim 1, the second methodology for decreasing a polling frequency of the buffer pool to a predetermined minimum polling rate if a predetermined amount of time has passed without any vendor-specific messages being stored into the fixed-size buffer pool.

16. In a system for temporarily storing selected vendor-specific messages into a fixed-size buffer pool and periodically polling the buffer pool to empty the buffer pool and transfer the selected vendor-specific messages to a disk file controlled by a host computer, an adapter for assisting in storing the selected vendor-specific messages into the buffer pool and transferring them to the disk file, comprising:

logic for generating the vendor-specific messages and selecting certain types of the vendor-specific messages for logging in accordance with a configurable logging level; and

a device driver installable into kernel space in the host computer for allocating the fixed-size buffer pool in the host computer upon initialization of the device driver and for managing a storing and retrieval of the messages into the buffer pool.

17. The adapter as recited in claim 16, the device driver for generating a reply to a service application containing a number of messages in the buffer pool and a total number of buffers in the buffer pool in response to a pool from the service application.

18. The adapter as recited in claim 17, the device driver for transmitting and removing one message from the buffer pool for each “

get next message”

request received at the device driver.

19. The adapter as recited in claim 16, wherein the adapter is a host bus adapter (HBA) for managing a transfer of information between the host computer and a storage area network.

20. The adapter as recited in claim 19, wherein the HBA manages the transfer of information between the host computer and an iSCSI-compatible storage area network.

21. A storage area network (SAN) comprising the adapter of claim 20, wherein an iSCSI network is coupled to the HBA and one or more storage devices are coupled to the iSCSI network.

22. The adapter as recited in claim 19, wherein the HBA manages the transfer of information between the host computer and fibre channel-compatible storage area network.

23. A storage area network (SAN) comprising the adapter of claim 22, wherein a fibre channel network is coupled to the HBA and one or more storage devices are coupled to the fibre channel network.

24. A method for storing selected vendor-specific adapter card messages into a disk file controlled by a host computer, comprising:

allocating a fixed-size buffer pool in the host computer for receiving and storing the selected vendor-specific messages;

periodically polling the buffer pool retrieve and remove the selected vendor-specific messages from the buffer pool and store the selected vendor-specific messages in the disk file;

increasing a polling frequency of the buffer pool according to a first methodology if buffer pool utilization is at or above a first predetermined threshold; and

decreasing the polling frequency of the buffer pool according to a second methodology if the buffer pool utilization is below a second predetermined threshold for a predetermined number of consecutive polling periods to account for multiple bursts of vendor-specific messages occurring within a period of vendor-specific message inactivity.

25. The method as recited in claim 24, further comprising executing a device driver in kernel space for managing the storing and retrieval of the messages from the buffer pool.

26. The method as recited in claim 25, further comprising allocating the fixed-sized buffer pool upon initialization of the device driver.

27. The method as recited in claim 25, wherein in response to a poll from a service application in user space, the method further comprises generating a reply to the service application containing a number of messages in the buffer pool and a total number of buffers in the buffer pool.

28. The method as recited in claim 27, the method further comprising issuing one “

get next message”

request from the service application to the device driver for each message in the buffer pool, and transmitting one message from the buffer pool to the service application and removing one message from the buffer pool for each “

get next message”

request received at the device driver.

29. The method as recited in claim 28, further comprising storing all messages into the disk file once all messages have been received in user space.

30. The method as recited in claim 27, further comprising computing the buffer pool utilization by dividing the number of messages in the buffer pool by the total number of buffers in the buffer pool.

31. A host computer for periodically polling selected vendor-specific messages stored into a fixed-size buffer pool to empty the buffer pool and transfer the selected vendor-specific messages to a disk file, comprising:

a fixed-size buffer pool for receiving and storing the selected vendor-specific messages;

a device driver installable into kernel space in the host computer for allocating the fixed-size buffer pool upon initialization of the device driver and for managing a storing and retrieval of the messages into the buffer pool; and

at least one processor in the host computer programmed for executing a service application in user space in the host computer to periodically poll the buffer pool, retrieve the selected vendor-specific messages from the buffer pool, store the selected vendor-specific messages in the disk file, increase a polling frequency of the buffer pool according to a first methodology if buffer pool utilization is at or above a first predetermined threshold, and decrease the polling frequency of the buffer pool according to a second methodology if the buffer pool utilization is below a second predetermined threshold for a predetermined number of consecutive polling periods to account for multiple bursts of vendor-specific messages occurring within a period of vendor-specific message inactivity.

32. The host computer as recited in claim 31, the first methodology for increasing a polling frequency of the buffer pool to a predetermined maximum polling rate if the buffer pool utilization is at or above the first predetermined threshold, and maintaining this maximum polling rate until the buffer pool utilization falls below the first predetermined threshold.

33. The computer as recited in claim 31, the second methodology for decreasing a polling frequency of the buffer pool to a predetermined minimum polling rate if a predetermined amount of time has passed without any vendor-specific messages being stored into the fixed-size buffer pool.

34. The host computer as recited in claim 31, the device driver for generating a reply to the service application containing a number of messages in the buffer pool and a total number of buffers in the buffer pool in response to a poll from the service application.

35. The host computer as recited in claim 34, the service application for computing the buffer pool utilization by dividing the number of messages in the buffer pool by the total number of buffers in the buffer pool.

36. The host computer as recited in claim 31, the service application for issuing one “

get next message”

request to the device driver for each message in the buffer pool, and the device driver for transmitting and removing one message from the buffer pool for each “

get next message”

request received at the device driver.

37. The host computer as recited in claim 36, the service application for storing all messages into the disk file once all messages have been received in user space.

38. A storage area network (SAN) comprising the host computer of claim 31, wherein an iSCSI network is coupled to the host computer and one or more storage devices are coupled to the iSCSI network.

39. A storage area network (SAN) comprising the host computer of claim 31, wherein a fibre channel network is coupled to the host computer and one or more storage devices are coupled to the fibre channel network.