Dynamically self-adjusting polling mechanism

• US 20040236880A1
• Filed: 05/19/2003
• Published: 11/25/2004
• Est. Priority Date: 05/19/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Emulex Corporation (Broadcom, Inc.)
• Inventors: Barrett, David Michael
• Granted Patent: US 6,931,460 B2
• Time in Patent Office: Days
• US Class Current: 710/52
• 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 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 messages;

a fixed-size buffer pool in the host computer for receiving and storing the 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 messages from the buffer pool, and store the messages in the disk file.

2. The system as recited in claim 1 wherein the logic generates the messages at a rate that cannot be controlled, the at least one processor further programmed for polling the buffer pool at a controllable polling frequency, and a time between polls represents one polling period.

3. The system as recited in claim 2, the at least one processor further programmed for increasing the polling frequency of the buffer pool if buffer pool utilization is at or above a predetermined threshold, and for decreasing the polling frequency of the buffer pool if the buffer pool utilization is below the predetermined threshold.

4. The system as recited in claim 3, the at least one processor further programmed for increasing the polling frequency by a first predetermined percentage if the buffer pool utilization is at or above the predetermined threshold.

5. The system as recited in claim 3, the at least one processor further programmed for decreasing the polling frequency by a second predetermined percentage if the buffer pool utilization is below the predetermined threshold for a predetermined number of consecutive polling periods.

6. The system as recited in claim 3, 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.

7. The system as recited in claim 6, the at least one processor further programmed for allocating the fixed-sized buffer pool upon initialization of the device driver.

8. The system as recited in claim 6, 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.

9. The system as recited in claim 8, the at least one processor further programmed in accordance with the service application for issuing one “

get next message”

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.

10. The system as recited in claim 9, the at least one processor further programmed for storing all messages into the disk file once all messages have been received in user space.

11. The system as recited in claim 8, 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.

12. The system as recited in claim 1, wherein the messages are vendor-specific messages.

13. The system as recited in claim 12, the logic for generating the vendor-specific messages in accordance with a configurable logging level.

14. The system as recited in claim 3, 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.

15. The system as recited in claim 14, wherein the HBA manages the transfer of information between the host computer and an iSCSI-compatible storage area network.

16. The system as recited in claim 14, wherein the HBA manages the transfer of information between the host computer and an fibre channel-compatible storage area network.

17. A storage area network (SAN) comprising the system of claim 15, wherein an iSCSI network is coupled to the HBA and one or more storage devices are coupled to the iSCSI network.

18. A storage area network (SAN) comprising the system of claim 16, wherein a fibre channel network is coupled to the HBA and one or more storage devices are coupled to the fibre channel network.

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

an adapter card couplable to the host computer, comprising

logic for generating the messages, 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; and

a storage medium readable by the host computer containing a service application loadable into user space in the host computer and executable by the host computer for periodically polling the buffer pool, transferring the messages from the buffer pool and storing the messages in the disk file.

20. The adapter as recited in claim 19 wherein the logic generates the messages at a rate that cannot be controlled and the service application polls the buffer pool at a controllable polling frequency, and a time between polls represents one polling period.

21. The adapter as recited in claim 20, the service application for increasing the polling frequency of the buffer pool if buffer pool utilization is at or above a predetermined threshold, and for decreasing the polling frequency of the buffer pool if the buffer pool utilization is below the predetermined threshold.

22. The adapter as recited in claim 21, the service application for increasing the polling frequency by a first predetermined percentage if the buffer pool utilization is at or above the predetermined threshold.

23. The adapter as recited in claim 21, the service application for decreasing the polling frequency by a second predetermined percentage if the buffer pool utilization is below the predetermined threshold for a predetermined number of consecutive polling periods.

24. The adapter as recited in claim 21, 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.

25. The adapter as recited in claim 24, 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.

26. The adapter as recited in claim 25, the service application for storing all messages into the disk file once all messages have been received in user space.

27. The adapter as recited in claim 24, 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.

28. The adapter as recited in claim 19, wherein the messages are vendor-specific messages.

29. The adapter as recited in claim 28, the logic for generating the vendor-specific messages in accordance with a configurable logging level.

30. The adapter as recited in claim 21, 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.

31. The adapter as recited in claim 30, wherein the HBA manages the transfer of information between the host computer and an iSCSI-compatible storage area network.

32. The adapter as recited in claim 30, wherein the HBA manages the transfer of information between the host computer and an fibre channel-compatible storage area network.

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

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

35. A method for storing 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 messages; and

executing a service application in user space in the host computer to periodically poll the buffer pool, retrieve and remove the messages from the buffer pool, and store the messages in the disk file.

36. The method as recited in claim 35 wherein the messages are generated at a rate that cannot be controlled, the method further comprising polling the buffer pool at a controllable polling frequency, a time between polls representing one polling period.

37. The method as recited in claim 36, further comprising increasing the polling frequency of the buffer pool if buffer pool utilization is at or above a predetermined threshold, and decreasing the polling frequency of the buffer pool if the buffer pool utilization is below the predetermined threshold.

38. The method as recited in claim 37, further comprising increasing the polling frequency by a first predetermined percentage if the buffer pool utilization is at or above the predetermined threshold.

39. The method as recited in claim 37, further comprising decreasing the polling frequency by a second predetermined percentage if the buffer pool utilization is below the predetermined threshold for a predetermined number of consecutive polling periods.

40. The method as recited in claim 37, further comprising executing a device driver in kernel space for managing the storing and retrieval of the messages from the buffer pool.

41. The method as recited in claim 40, further comprising allocating the fixed-sized buffer pool upon initialization of the device driver.

42. The method as recited in claim 40, wherein in response to a poll from the 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.

43. The method as recited in claim 42, 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.

44. The method as recited in claim 43, further comprising storing all messages into the disk file once all messages have been received in user space.

45. The method as recited in claim 42, 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.

46. The method as recited in claim 35, wherein the messages are vendor-specific messages.

47. The method as recited in claim 46, further comprising generating the vendor-specific messages in accordance with a configurable logging level.