Event tracking hardware

• US 8,140,761 B2
• Filed: 12/04/2009
• Issued: 03/20/2012
• Est. Priority Date: 12/04/2009
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Ekanadham, Kattamuri, Park, Il
• Primary Examiner(s): Elmore, Stephen
• Application Number:
  US12/630,946
• Publication Number:
  US 20110138125A1
• Time in Patent Office: 837 Days
• Field of Search: 711/123, 711/133, 711/156, 711/159, 711/221, 702/127, 710/18, 714/39, 719/318
• US Class Current: 711/123
• CPC Class Codes: G06F 11/348 Circuit details, i.e. tracer hardware
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 12/0897 with two or more cache hierarchy levels with multilevel cache hierarchies G06F12/0811
• CPC Class Codes: G06F 2201/88 Monitoring involving counting

Abstract

An event tracking hardware engine having N (≧2) caches is invoked when an event of interest occurs, using a corresponding key. The event tracking engine stores a cumulative number of occurrences for each one of the different kinds of events, and searches in the N caches for an entry for the key. When an entry for the key is found, the engine increments the number of occurrences if no overflow of the cumulative number of occurrences would occur. However, if the incrementing would cause overflow, then instead of incrementing the cumulative number of occurrences, the engine promotes the entry for the event of interest to a next higher cache.

Claims

1. A method comprising the steps of:

detecting multiple occurrences of a plurality of different kinds of events of interest;

upon each of said occurrences, invoking an event tracking hardware engine having N caches, N being at least two, using a key of a type corresponding to a corresponding one of said different kinds of events of interest, such that said event tracking hardware engine stores, for each of said different kinds of events of interest, a corresponding cumulative number of occurrences, by carrying out the following steps;

searching in said N caches for an entry for said key;

if an entry for said key is found, and no overflow of said corresponding cumulative number of occurrences for said entry for said key would occur by incrementing said corresponding cumulative number of occurrences, incrementing said corresponding cumulative number of occurrences;

if said entry for said key is found, and overflow of said corresponding cumulative number of occurrences for said entry for said key would occur by incrementing said corresponding cumulative number of occurrences, promoting said entry from a given one of said N caches in which said entry exists to a next highest one of said N caches; and

if said entry for said key is not found, entering said entry for said key in a zeroth one of said N caches with said corresponding cumulative number of occurrences being initialized.

2. The method of claim 1, further comprising periodically preparing a list of said different kinds of events of interest together with said corresponding cumulative numbers of occurrences.

3. The method of claim 2, further comprising preparing a histogram based on said list of said different kinds of events of interest.

4. The method of claim 2, further comprising executing a program on a computer processor, wherein said different kinds of events of interest are events associated with execution of said program.

5. The method of claim 4, wherein said computer processor is part of an autonomic computing system, further comprising:

detecting at least one anomaly with said autonomic computing system, based on said list of said different kinds of events of interest; and

facilitating initiation of corrective action to correct said at least one anomaly.

6. The method of claim 4, wherein said different kinds of events of interest comprise at least branch misses and cache misses.

7. The method of claim 6, wherein said keys indicate whether a given one of said different kinds of events of interest comprises a branch miss or a cache miss, and further indicate at least a corresponding instruction address.

8. The method of claim 7, wherein said keys further indicate a corresponding data address.

9. The method of claim 2, wherein said list is ordered from a highest level one of said N caches to a lowest level one of said N caches, and from highest to lowest number of occurrences within a given one of said N caches.

10. The method of claim 2, further comprising when, in said promoting step, said next highest one of said N caches is full, selecting a victim entry in said next highest one of said N caches to make room for said promoted entry.

11. A method comprising the steps of:

detecting multiple occurrences of a plurality of different kinds of events of interest;

upon each of said occurrences, invoking an event tracking hardware engine having N caches, N being at least two, using a key of a type corresponding to a corresponding one of said different kinds of events of interest, such that said event tracking hardware engine stores, for each of said different kinds of events of interest, a corresponding cumulative number of occurrences, by carrying out the following steps;

searching in a zeroth one of said N caches for an entry for said key;

if an entry for said key is found in said zeroth one of said N caches, and no overflow of said corresponding cumulative number of occurrences for said entry for said key would occur by incrementing said corresponding cumulative number of occurrences, incrementing said corresponding cumulative number of occurrences;

if said entry for said key is found in said zeroth one of said N caches, and overflow of said corresponding cumulative number of occurrences for said entry for said key would occur by incrementing said corresponding cumulative number of occurrences, promoting said entry from said zeroth one of said N caches in which said entry exists to a next highest one of said N caches; and

if said entry for said key is not found, entering said entry for said key in said zeroth one of said N caches with said corresponding cumulative number of occurrences being initialized.

12. The method of claim 11, further comprising periodically preparing a list of said different kinds of events of interest together with said corresponding cumulative numbers of occurrences.

13. The method of claim 12, further comprising preparing a histogram based on said list of said different kinds of events of interest.

14. The method of claim 12, further comprising executing a program on a computer processor, wherein said different kinds of events of interest are events associated with execution of said program.

15. The method of claim 14, wherein said computer processor is part of an autonomic computing system, further comprising:

detecting at least one anomaly with said autonomic computing system, based on said list of said different kinds of events of interest; and

facilitating initiation of corrective action to correct said at least one anomaly.

16. The method of claim 14, wherein said different kinds of events of interest comprise at least branch misses and cache misses.

17. The method of claim 16, wherein said keys indicate whether a given one of said different kinds of events of interest comprises a branch miss or a cache miss, and further indicate at least a corresponding instruction address.

18. The method of claim 17, wherein said keys further indicate a corresponding data address.

19. The method of claim 12, wherein said list is ordered from a highest level one of said N caches to a lowest level one of said N caches, and from highest to lowest number of occurrences within a given one of said N caches.

20. The method of claim 12, further comprising when, in said promoting step, said next highest one of said N caches is full, selecting a victim entry in said next highest one of said N caches to make room for said promoted entry.

21. An event tracking engine apparatus comprising:

a plurality of caches; and

a corresponding plurality of control circuits;

said plurality of caches and said corresponding plurality of control circuits being cooperatively configured to;

receive indications of multiple occurrences of a plurality of different kinds of events of interest, said indications being received as keys;

store a corresponding cumulative number of occurrences for each of said different kinds of events of interest, by carrying out the following steps upon receipt of each given one of said keys;

searching in said caches for an entry for given one of said keys;

if an entry for given one of said keys is found, and no overflow of said corresponding cumulative number of occurrences for said entry for given one of said keys would occur by incrementing said corresponding cumulative number of occurrences, incrementing said corresponding cumulative number of occurrences;

if said entry for given one of said keys is found, and overflow of said corresponding cumulative number of occurrences for said entry for given one of said keys would occur by incrementing said corresponding cumulative number of occurrences, promoting said entry from a given one of said caches in which said entry exists to a next highest one of said caches; and

if said entry for given one of said keys is not found, entering said entry for given one of said keys in a zeroth one of said caches with said corresponding cumulative number of occurrences being initialized.

22. The event tracking engine apparatus of claim 21, wherein said plurality of caches and said corresponding plurality of control circuits are cooperatively configured such that, in said promoting step, if said next highest one of said caches is full, a victim entry is selected in said next highest one of said caches to make room for said promoted entry.

23. An event tracking engine apparatus comprising:

a plurality of caches; and

a corresponding plurality of control circuits;

said plurality of caches and said corresponding plurality of control circuits being cooperatively configured to;

receive indications of multiple occurrences of a plurality of different kinds of events of interest, said indications being received as keys;

store a corresponding cumulative number of occurrences for each of said different kinds of events of interest, by carrying out the following steps upon receipt of each given one of said keys;

searching in a zeroth one of said caches for an entry for said given one of said keys;

if an entry for said given one of said keys is found in said zeroth one of said caches, and no overflow of said corresponding cumulative number of occurrences for said entry for said key would occur by incrementing said corresponding cumulative number of occurrences, incrementing said corresponding cumulative number of occurrences;

if said entry for said given one of said keys is found in said zeroth one of said caches, and overflow of said corresponding cumulative number of occurrences for said entry for said given one of said keys would occur by incrementing said corresponding cumulative number of occurrences, promoting said entry from said zeroth one of said caches in which said entry exists to a next highest one of said caches; and

if said entry for said given one of said keys is not found, entering said entry for said given one of said keys in said zeroth one of said caches with said corresponding cumulative number of occurrences being initialized.

24. The event tracking engine apparatus of claim 23, wherein said plurality of caches and said corresponding plurality of control circuits are cooperatively configured such that, in said promoting step, if said next highest one of said caches is full, a victim entry is selected in said next highest one of said caches to make room for said promoted entry.