Mechanism for creating friendly transactions with credentials

• US 10,270,773 B2
• Filed: 11/04/2015
• Issued: 04/23/2019
• Est. Priority Date: 11/04/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bradbury, Jonathan D., Busaba, Fadi Y., Gschwind, Michael Karl, Salapura, Valentina, Schwarz, Eric M., Shum, Chung-Lung K.
• Primary Examiner(s): Padmanabhan, Mano
• Assistant Examiner(s): Cheong, Andrew J
• Application Number:
  US14/932,737
• Publication Number:
  US 20170123876A1
• Time in Patent Office: 1,266 Days
• CPC Class Codes: G06F 11/14 Error detection or correction of the data by redundancy in operation G06F11/16 takes precedence
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 12/0828 with concurrent directory accessing, i.e. handling multiple concurrent coherency transactions
• CPC Class Codes: G06F 12/0877 Cache access modes
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• CPC Class Codes: G06F 21/00 Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources

Abstract

One or more transactions may request or be assigned tokens within a transactional memory environment. A transaction may be created by at least one thread. A first transaction that includes a first token type may be received. A request may be received for a for a potential conflict check between the first transaction and a second transaction. In response to receiving the transaction potential conflict check, the first transaction and the second transaction are determined to be conflicting or not conflicting. The second transaction is assigned a token type in response to the determination of the transaction potential conflict check between the first transaction and the second transaction.

Claims

1. A system for assigning tokens to transactions in a transactional memory execution environment, comprising:

a memory;

a processor device; and

a system controller communicatively coupled to the processor device and the memory, wherein the system controller is configured to;

receive a first transaction having a first token of a first token type associated with the first transaction;

receive a request for a transaction potential conflict check between the first transaction and a second transaction, wherein the first transaction is using a cache line;

determine, in response to receiving the request for the transaction potential conflict check, whether the first transaction and the second transaction are conflicting, wherein determining whether the first transaction and the second transaction are conflicting includes at least determining whether the first transaction and the second transaction have a shared address space within the memory, the memory having one or more memory partitions supporting one or more address spaces;

in response to determining that the first transaction and the second transaction do not have the shared address space within the memory, assign the second transaction a second token of the first token type identical to the first token based on the transaction potential conflict check between the second transaction and the first transaction; and

suppress detection of cache coherent conflicts in response to assigning the second transaction the second token identical to the first token such that cache coherency protocols are ignored, wherein suppressing detection of the cache coherent conflicts allows the first transaction to write to the cache line and the second transaction to write to the cache line concurrently.

2. The system of claim 1, wherein the system controller is further configured to:

determine a completion of the first transaction;

reclaim, in response to the completion of the first transaction, the first token from the first transaction; and

return the reclaimed first token to a token pool which stores unused tokens.

3. The system according to claim 1, wherein the shared address space includes an overlapping address space.

4. The system according to claim 1, wherein determining that the first transaction and the second transaction do not have the shared address space within the memory includes determining that the first transaction and the second transaction share a memory partition.

5. The system according to claim 4, wherein determining that the first transaction and the second transaction do not have the shared address space within the memory further includes determining that the first transaction is within a first address space and the second transaction is within a second address space.

6. The system according to claim 1, wherein determining that the first transaction and the second transaction do not have the shared address space within the memory includes determining that the first transaction and the second transaction do not share a memory partition.

7. The system according to claim 1, wherein the cache line is within a cache level, the cache level including a cache protocol handler to compare token types and adjust the cache coherency protocol.

8. The system according to claim 7, wherein the cache level is a private cache.

9. The system according to claim 7, wherein the cache level is a shared cache.

10. The system according to claim 1, wherein the first transaction writes to a first part of the cache line and the second transaction writes to a second part of the cache line.

11. The system according to claim 1, wherein the first transaction and the second transaction write to a same part of the cache line.

12. The system according to claim 1,

wherein receiving the first transaction comprises:

receiving a request from the first transaction to access the cache line, and

granting ownership of the cache line to the first transaction; and

wherein receiving a request for the transaction potential conflict check comprises;

receiving a request from the second transaction to access the cache line while the first transaction is still active on the cache line.

13. A computer program product for assigning tokens to transactions in a transactional memory execution environment comprising a computer readable storage medium having a computer readable program stored therein, wherein the computer readable storage medium does not comprise a transitory signal per se, wherein the computer readable program, when executed on a computing device, causes the computing device to:

receive a first transaction having a first token of a first token type associated with the first transaction;

receive a request for a transaction potential conflict check between the first transaction and a second transaction, wherein the first transaction is using a cache line;

determine, in response to receiving the request for the transaction potential conflict check, whether the first transaction and the second transaction are conflicting, wherein determining whether the first transaction and the second transaction are conflicting includes at least determining whether the first transaction and the second transaction have a shared address space within a memory, the memory having one or more memory partitions supporting one or more address spaces;

in response to determining that the first transaction and the second transaction do not have the shared address space within the memory, assign the second transaction a second token of the first token type identical to the first token based on the transaction potential conflict check between the second transaction and the first transaction; and

suppress detection of cache coherent conflicts in response to assigning the second transaction the second token identical to the first token such that cache coherency protocols are ignored, wherein suppressing detection of the cache coherent conflicts allows the first transaction to write to the cache line and the second transaction to write to the cache line concurrently.

14. The computer program product of claim 13, wherein the computer readable program further causes the computing device to:

determine a completion of the first transaction;

reclaim, in response to the completion of the first transaction, the first token from the first transaction; and

return the reclaimed first token to a token pool which stores unused tokens.

15. A system for assigning tokens to transactions in a transactional memory environment, wherein a transaction is created by at least one thread, the system comprising:

a memory;

a processor device; and

a system controller communicatively coupled to the processor device and the memory, wherein the system controller is configured to;

receive a first transaction having a first token of a first token type associated with the first transaction;

receive a request for a transaction potential conflict check between the first transaction and a second transaction, wherein the first transaction is using a cache line;

determine, in response to receiving the request for the transaction potential conflict check, whether the first transaction and the second transaction are conflicting, wherein determining whether the first transaction and the second transaction are conflicting includes at least determining whether the first transaction and the second transaction have a shared address space within the memory, the memory having one or more memory partitions supporting one or more address spaces;

in response to determining that the first transaction and the second transaction do not have the shared address space within the memory, assign the second transaction a second token of a second token type different from the first token type based on the transaction potential conflict check between the second transaction and the first transaction, wherein the second token type is compatible with the first token type, wherein the first token type includes a compatibility list of a set of token types of which the first token type is compatible; and

suppress detection of cache coherent conflicts in response to assigning the second transaction the second token compatible with the first token such that cache coherency protocols are ignored, wherein suppressing detection of the cache coherent conflicts allows the first transaction to write to the cache line and the second transaction to write to the cache line concurrently.