As per definition, “” The CLDEMOTE instruction hints to hardware that the cache line that contains the linear address should be moved(“demoted”) from the cache(s) closest to the processor core to a level more distant from the processor core. This may accelerate subsequent accesses to the line by other cores in the same coherence domain, especially if the line was written by the core that demotes the line.”” The operating system/OS tells the processor core that a specific content of a cache (e.g. cache line) is not required in the lower level cache which is close to this core, and can easily be “demoted” to a higher cache level, but without flushing back to the main system Memory.DSO Gaming has more details. It's unknown how much performance could be gained with CLDEMOTE.
“CLDEMOTE” instruction is a “hint” to the hardware that it might help performance to move a cache line from the cache level(s) “closest” to the core to a cache level that is “further” from the core.
#Intel released the 39th edition of the ISA Extensions Reference with #AlderLake, #SapphireRapids clarifications.— InstLatX64 (@InstLatX64) June 3, 2020
SPR CPUID is 806Fx (Family 6 model 143). #CLDEMOTE will be supported!https://t.co/NK6XAb4EWt pic.twitter.com/1QtJ3c3Xjp