US 12,332,799 B2
Speculative request indicator in request message
Wesley Waylon Terpstra, San Mateo, CA (US); Eric Andrew Gouldey, Fort Collins, CO (US); Michael Klinglesmith, Chambéry (FR); and Henry Cook, Berkeley, CA (US)
Assigned to SiFive, Inc., Santa Clara, CA (US)
Filed by SiFive, Inc., San Mateo, CA (US)
Filed on Jun. 26, 2023, as Appl. No. 18/341,217.
Claims priority of provisional application 63/429,327, filed on Dec. 1, 2022.
Prior Publication US 2024/0184703 A1, Jun. 6, 2024
Int. Cl. G06F 12/0862 (2016.01); G06F 12/0811 (2016.01); G06F 12/0815 (2016.01)
CPC G06F 12/0862 (2013.01) [G06F 12/0811 (2013.01); G06F 12/0815 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method comprising:
providing, for a cache hierarchy, a messaging protocol used for transfer operations among agents in the cache hierarchy, the messaging protocol indicating acceptable cache coherency states for a cache block indicated in a request message; and
providing, in the messaging protocol for selection by an agent, a speculative request indicator when sending the request message, wherein the speculative request indicator differentiates between a demand request and a speculative request with respect to the cache block, wherein selection of the speculative request indicator includes at least selecting a bit for an invalid state.