Techniques to manage a flow cache

• US 20070192543A1
• Filed: 02/13/2006
• Published: 08/16/2007
• Est. Priority Date: 02/13/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Vipat, Harshawardhan, Kumar, Alok, Naik, Uday
• Granted Patent: US 7,555,608 B2
• Time in Patent Office: Days
• US Class Current: 711/133
• CPC Class Codes: G06F 12/0891 using clearing, invalidating or resetting means
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]

Abstract

Techniques are described herein that may be used to invalidate all entries in a table. For example, the table may be a flow cache. For example, an expiry time may be associated with one or more entries in the table. The expiry time of an entry may be initially set to the sum of the system time, the expiry time of the protocol associated with the entry, and a global time variable. To check if the entry is expired at any time, the current system time may be added to the global time variable and if the result is greater than the expiry time in the entry, then the entry is expired. To invalidate all the entries, the global time variable may be incremented by a large amount which may equal the maximum expiry time of all protocols. This may cause all entries to expire. New entries may be added using the new incremented value of the global time variable and will hence not expire.

Claims

1. An apparatus comprising:

logic to store entries in a flow cache;

logic to invalidate entries in the flow cache in part by increasing a time incrementing variable by a large increment;

logic to retrieve an entry from the flow cache in part in response to receipt of a packet;

logic to set a current time variable for the entry to be a sum of a current system time and the time incrementing variable; and

logic to determine whether the entry is valid in part based on the current time variable exceeding the expiration time of the entry.

2. The apparatus of claim 1, further comprising:

logic to update the entry in response to the entry being determined to be expired.

3. The apparatus of claim 2, further comprising:

logic to set the expiration time of the updated entry to be a sum of the current time variable and an expiration time of a protocol associated with the entry.

4. The apparatus of claim 1, wherein the large increment comprises the maximum of the expiry time of all protocols associated with entries in the flow cache.

5. The apparatus of claim 1, wherein the logic to invalidate entries is to invalidate all entries in the flow cache in response to when any classification rule is updated.

6. A method comprising:

invalidating entries in a table in part by increasing a time incrementing variable by a large increment;

identifying an entry in the table;

setting a current time variable for the entry to be a sum of a current system time and the time incrementing variable; and

determining whether the entry is valid in part based on the current time variable exceeding an expiration time of the entry.

7. The method of claim 6, further comprising:

updating the entry in response to the entry being determined to be expired.

8. The method of claim 7, further comprising:

setting the expiration time of the updated entry to be a sum of the current time variable and an expiration time of a protocol associated with the entry.

9. The method of claim 6, wherein the large increment comprises the maximum of the expiry time of all protocols associated with entries in the table.

10. The method of claim 6, further comprising:

invalidating all entries in the table in response to when any classification rule is updated.

11. The method of claim 6, wherein the table comprises a flow cache table.

12. The method of claim 6, wherein identifying an entry in the table comprises determining a hash index based on a portion of a packet.

13. A computer-readable medium comprising instructions stored thereon which when executed by a machine cause the machine to:

invalidate entries in a flow cache in part by increasing a time incrementing variable by a large increment;

determine a hash index based on a portion of a packet;

determine an entry from the flow cache based on the hash index; and

set a current time variable for the entry to be a sum of a current system time and the time incrementing variable, and

determine whether the entry is valid in part based on the current time variable exceeding an expiration time of the entry.

14. The computer-readable medium of claim 13, further comprising instructions stored thereon which when executed by a machine cause the machine to:

update the entry in response to the entry determined to be expired.

15. The computer-readable medium of claim 14, further comprising instructions stored thereon which when executed by a machine cause the machine to:

set the expiration time of the updated entry to be a sum of the current time variable and an expiration time of a protocol associated with the entry.

16. The computer-readable medium of claim 13, wherein the large increment comprises the maximum of the expiry time of all protocols associated with entries in the flow cache.

17. The computer-readable medium of claim 13, further comprising instructions stored thereon which when executed by a machine cause the machine to:

invalidate all entries in the flow cache in response to when any classification rule is updated.

18. A system comprising:

a system fabric;

a line card comprising;

a packet processor;

logic to store entries in a flow cache,

logic to invalidate entries in the flow cache in part by increasing a time incrementing variable by a large increment,

logic to retrieve an entry from the flow cache in part in response to receipt of a packet,

logic to set a current time variable for the entry to be a sum of a current system time and the time incrementing variable, and

logic to determine whether the entry is valid in part based on the current time variable exceeding the expiration time of the entry.

19. The system of claim 18, wherein the line card further comprises:

logic to update the entry in response to the entry determined expired.

20. The system of claim 19, wherein the line card further comprises:

logic to set the expiration time of the updated entry to be a sum of the current time variable and an expiration time of a protocol associated with the entry.

21. The system of claim 18, wherein the large increment comprises the maximum of the expiry time of all protocols associated with entries in the flow cache.

22. The system of claim 18, wherein the logic to invalidate entries is to invalidate all entries in the flow cache in response to when any classification rule is updated.