Directory cache supporting non-atomic input/output operations

摘要

Responsive to receiving a write request for a cache line from an input/output device, a caching agent of a first processor determines that the cache line is managed by a home agent of a second processor. The caching agent sends an ownership request for the cache line to the second processor. A home agent of the second processor receives the ownership request, generates an entry in a directory cache for the cache line, the entry identifying the remote caching agent as having ownership of the cache line, and grants ownership of the cache line to the remote caching agent. Responsive to receiving the grant of ownership for the cache line from the home agent an input/output controller of the first processor adds an entry for the cache line to an input/output write cache, the entry comprising a first indicator that the cache line is managed by the home agent of the second processor.

主权项

1. A method comprising:
responsive to receiving a write request for a cache line from a I/O device, determining, by a caching agent of a first processor, that the cache line is managed by a home agent of a second processor; sending an ownership request for the cache line to the second processor; and responsive to receiving a grant of ownership for the cache line from the home agent of the second processor, adding an entry for the cache line to an input/output (I/O) write cache by an I/O controller associated with the first processor, the entry comprising a first indicator that the cache line is managed by the home agent of the second processor.