Transactional memory execution utilizing virtual memory

• US 7,685,365 B2
• Filed: 09/30/2004
• Issued: 03/23/2010
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Rajwar, Ravi, Herlihy, Maurice P.
• Primary Examiner(s): TSAI, SHENG JEN
• Application Number:
  US10/956,178
• Publication Number:
  US 20060085588A1
• Time in Patent Office: 2,000 Days
• Field of Search: 711/100, 711/118
• US Class Current: 711/118
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence

Abstract

Embodiments of the invention relate to transactional memory execution utilizing virtual memory. A processor includes a local transactional cache and a resource manager. The resource manager responsive to a transactional memory transaction request from a requesting thread determines whether the local transactional cache is capable of accommodating the transactional memory transaction request and, if so, the local transactional caches performs the transactional memory transaction. However, if the local transactional cache is not capable of accommodating the transactional memory transaction request, data for the transactional memory transaction request is overflowed into an application'"'"'s virtual address space associated with the requesting thread.

Claims

1. An apparatus comprising:

a processor including

a local transactional cache;

a resource manager, responsive to a transactional memory request, which is to reference an original address and is to be associated with a requesting thread, to determine whether the local transactional cache is capable of accommodating the transactional memory request, wherein the local transactional cache is utilized to perform the transactional memory request in response to the local transactional cache being capable of accommodating the transactional memory request;

a transaction address walker to associate a new address, which is within an address space for the requesting thread, with the original address in an entry to be held in the address space for the requesting thread and to manage overflow of data associated with the transactional memory request from the original address to the new address in response to the local transactional cache not being capable of accommodating the transactional memory request; and

a conflict detection filter (CDF) to indicate the original address has been overflowed in response to the local transactional cache not being capable of accommodating the transactional memory request, wherein the transaction address walker, in response to a subsequent transactional memory request to reference the original address, is not to access the entry to associate the new address with the original address based on the CDF indicating the original address has been overflowed.

2. The apparatus of claim 1, further comprising a transaction address table translation table (XATT) to be held in a portion of physical memory corresponding to the address space for the requesting thread, wherein the transaction address walker to associate the new address with the original address in the entry comprises the transaction address walker to initiate a store of at least the original address and the new address to an entry of the XATT.

3. The apparatus of claim 2, wherein the address space includes a virtual address space for the requesting thread, the original address includes a virtual address, and the new address includes a new virtual address within the virtual address space, and wherein the processor further includes address translation logic to translate the virtual address space to a physical address space including the portion of physical memory, to translate the original virtual address to an original physical address and to translate the new virtual address to a new physical address within the physical address space, the new physical address being different than the original physical address.

4. The apparatus of claim 3, wherein the transaction address walker is further to initiate a store to the entry of the original physical address, the new physical address, and a transaction action pointer (XPTR) to represent a state of a current transaction associated with the transactional memory request.

5. The apparatus of claim 4, wherein the state of a current transaction is selected from a group consisting of local, overflow, active, swapped, running, aborted, and committed.

6. The apparatus of claim 2, wherein the processor further comprises a translation buffer to cache at least a portion of the entry of the XATT.

7. The apparatus of claim 4, wherein responsive to an attempted commit of an overflowed transaction including the transactional memory request, the XATT walker checks the XPTR held in the entry of the XATT and in response to the XPTR of the XATT representing an abort state, the overflowed transaction is aborted.

8. The apparatus of claim 2, wherein the XATT is to hold entries for every overflowed transaction associated with the requesting thread, and wherein a second XATT is to hold entries for every overflowed transaction associated with a second thread.

9. A method comprising:

determining whether a cache resident within a processor is capable of accommodating a transactional memory request from a requesting thread associated with a virtual address space with a resource manager implemented inside the processor, the transactional memory request being associated with an original address;

performing the transactional memory request with the local cache in response to the resource manager determining the local cache is capable of accommodating the transactional memory request;

in response to the resource manager determining the local cache is not capable of accommodating the transactional memory request;

assigning a new address to the transactional memory request within an entry of a transaction address translation table (XATT), the new address and the XATT being within the virtual address space associated with the thread;

updating a conflict detection filter CDF to indicate the original address has been overflowed;

managing data for the transactional memory request utilizing the new address; and

determining a conflict without an access to the table based on the CDF indicating the original address has been overflowed in response to a subsequent access to the original address.

10. The method of claim 9, wherein a XATT walker within the processor is to assign the new address by operating on the XATT stored in physical memory associated with the virtual address space.

11. The method of claim 10, wherein assigning a new address includes assigning a new virtual address and a new physical address to the transactional memory request, wherein assigning the new virtual address and the new physical address to the transactional memory request includes updating an entry in the XATT stored in physical memory associated wit the virtual address space to hold the new virtual address, an original virtual address, the new physical address, and an original physical address.

12. The method of claim 11, further comprising assigning a state of a current transaction including the transactional memory request within the entry in the XATT.

13. The method of claim 12, wherein the state of a current transaction is one of local or overflow.

14. A machine-readable medium of a storage device having tangibly stored thereon instructions, which when executed by a machine, cause the machine to perform the following operations comprising:

determining whether a transactional memory store request referencing an original address for store data from a requesting thread associated with a virtual address space is to overflow a local memory within a processor;

performing the transactional memory transaction with the local memory in response to determining the transactional memory store request is not to overflow the local memory;

in response to determining the transactional memory store request is to overflow the local memory

assigning, within a table, a new address associated with the virtual address space to buffer the store data until an end of a transaction including the transactional memory store request,

updating a conflict detection filter CDF to indicate the original address has overflowed; and

determining a conflict without an access to the table based on the CDF indicating the original address has been overflowed in response to a subsequent access to the original address.

15. The machine-readable medium of claim 14, wherein assigning the new address associated with the virtual address space comprises a XATT walker within the processor to update an entry of a XATT table held in physical memory coupled to the processor to hold the new address and the original address.

16. The machine-readable medium of claim 15, wherein the original address includes an original virtual address and the new address includes a new virtual address within the virtual address space.

17. The machine-readable medium of claim 15, wherein the original address includes an original virtual address, when translated by a translation buffer in the processor, to reference an original physical address, and wherein the new address includes a new physical address, when translated by the translation buffer, to reference a new virtual address within the virtual address space.

18. The machine-readable medium of claim 17, wherein the entry of the XATT table is to hold the original virtual address, the new virtual address, the original physical address, the new physical address, and a state of a transaction including the transactional memory store request.

19. The machine-readable medium of claim 14, further comprising instructions to cause the machine to copy the store data from the new address to the original address in response to a commit of a transaction including the transactional memory store request.

20. The machine-readable medium of claim 14, further comprising instructions to cause the machine to discard the store data from the new address in response to an abort of a transaction including the transactional memory store request.

21. A computer system comprising:

a system memory to hold a transactional translation table within an application address space;

a processor coupled to the system memory, the processor including

a local cache;

a resource manager to determine whether the local cache is capable of accommodating a transactional memory request from a requesting thread of an associated application, which is to be associated with the application address space, the transactional memory request to reference an original address; and

a transactional translation table walker to initiate an update of an entry of the transactional translation table to hold a new address associated with the original address, the new address being within the application address space, wherein the new address is to hold overflow data associated with the transactional memory request; and

conflict detection logic to hold references to original addresses that have overflowed the local cache, and wherein a conflict from a subsequent transactional memory request is capable of being detected based on the references to the original addresses held in the conflict detection logic without the transactional translation table walker accessing the transactional translation table held within the system memory.

22. The computer system of claim 21, wherein the processor further includes translation logic to translate virtual addresses to physical address, and wherein the original address includes an original virtual address, when translated by the translation logic, to reference an original physical address, and the new address includes a new virtual address, when translated by the translation logic, to reference a new physical address of a physical memory location in the system memory within the application address space.

23. The computer system of claim 22, wherein the processor further includes a transaction translation cache to cache recently updated entries of the transactional translation table.

24. The computer system of claim 21, wherein the local cache includes a transactional cache separate from a data cache within the processor.

25. The computer system of claim 21, wherein the local cache includes data cache, which is also to be utilized as a transactional cache.

26. The computer system of claim 22, wherein the entry of the transactional table is to hold the original virtual address, the new virtual address, the original physical address, the new physical address, and a state of a transaction including the transactional memory request.

27. The computer system of claim 21, wherein the transactional translation table within the application address space is to only be associated with the single transaction including the transactional memory request.

28. The computer system of claim 21, wherein the transactional translation table within the application address space is to be associated with all transactions from the requesting thread of the associated application.

29. An apparatus comprising:

a processor including

a local memory;

execution resources to execute a thread that includes a transaction having at least a transactional store operation to reference store data and an original virtual address for the store data, the thread to be associated with a virtual address space;

translation logic to translate virtual addresses within the virtual address space to physical addresses of physical memory to be associated with the processor;

overflow logic to determine if the transactional store operation, when received, is to overflow the local memory;

transaction logic to associate, within a table, a new virtual address, which is within the virtual address space to be associated with the thread, with the original virtual address in response to the overflow logic determining the transactional store operation is to overflow the local memory, wherein the new virtual address, when translated by the translation logic, is to reference a new physical address of the physical memory to hold the store data; and

conflict detection logic to track the original physical address in response to the overflow logic determining the transactional store operation is to overflow the local memory, and wherein, in response to a subsequent transactional memory request referencing the address, the transaction logic is capable of determining a conflict based on the original physical address tracked in the conflict detection logic without a lookout to the table.

30. The apparatus of claim 29, wherein the local memory includes a cache memory;

the execution resources are capable of executing multiple threads, including the thread, at least partially in parallel;

the original virtual address, when translated by the translation logic, is to reference an original physical address of the physical memory; and

the physical memory includes a memory device to be coupled to the processor within a computer system.

31. The apparatus of claim 30, wherein the transaction logic to associate the new virtual address with the original virtual address comprises the transaction logic to initiate a write to a table to be held in the physical memory to update an entry of the table to hold the new virtual address and the original virtual address.

32. The apparatus of claim 31, wherein the processor further includes a transaction translation cache to cache at least a portion of the entry of the table in response to the transaction logic initiating the write to the table.