[PATCH v5 2/5] perf: Add SNOOP_PEER flag to perf mem data struct

Liang, Kan kan.liang at linux.intel.com
Fri Apr 22 14:08:34 PDT 2022



On 4/22/2022 2:49 PM, Ali Saidi wrote:
> On Wed, 20 Apr 2022 18:43:28, Kan Liang wrote:
>> On 4/8/2022 3:53 PM, Ali Saidi wrote:
>>> Add a flag to the perf mem data struct to signal that a request caused a
>>> cache-to-cache transfer of a line from a peer of the requestor and
>>> wasn't sourced from a lower cache level.
>>
>> It sounds similar to the Forward state. Why can't the
>> PERF_MEM_SNOOPX_FWD be reused?
> 
> Is there a definition of SNOOPX_FWD i can refer to? Happy to use this instead if
> the semantics align between architectures.
> 

+ Andi

As my understanding, the SNOOPX_FWD means the Forward state, which is a 
non-modified (clean) cache-to-cache copy.
https://en.wikipedia.org/wiki/MESIF_protocol

Thanks,
Kan



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