Ambiguous virtual channels
View Patent ↗An apparatus comprises a first plurality of buffers configured to store operations belonging to a first virtual channel and a control circuit coupled to the first plurality of buffers. The first virtual channel includes first operations and second operations, wherein each of the first operations depend on at least one of the second operations during use. A first number of the first operations is less than or equal to a maximum. It is ambiguous, for a first received operation in the first virtual channel, whether the first received operation is one of the first operations or the second operations. A total number of the first plurality of buffers exceeds the maximum.
1. A cache comprising:
a cache memory;
one or more read buffers configured to store read operations for the cache memory;
one or more write buffers configured to store write operations for the cache memory; and
a control circuit coupled to the one or more write buffers, wherein, in response to a hit of a probe on a first write operation in the one or more write buffers, the control circuit is configured to change a state of the first write operation to invalid.
2. The cache as recited in claim 1 wherein the control circuit is configured to respond to the probe with an indication that a cache block corresponding to the probe is invalid in the cache.
3. The cache as recited in claim 1 wherein the first write operation updates a second state of a cache block in the cache memory, and wherein the second state is updated to invalid in response to the first write operand if the state is invalid.
4. The cache as recited in claim 3 wherein, if the hit of the probe on the first write operation does not occur, the state of the first write operation is modified and the second state in the cache memory is updated to modified in the cache memory.