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    Subject[PATCH v7 2/5] perf tools: sync addition of PERF_MEM_SNOOPX_PEER
    Date
    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. The line being moved from one
    peer cache to another has latency and performance implications. On Arm64
    Neoverse systems the data source can indicate a cache-to-cache transfer
    but not if the line is dirty or clean, so instead of overloading HITM
    define a new flag that indicates this type of transfer.

    Signed-off-by: Ali Saidi <alisaidi@amazon.com>
    Reviewed-by: Leo Yan <leo.yan@linaro.org>
    ---
    tools/include/uapi/linux/perf_event.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
    index d37629dbad72..7b88bfd097dc 100644
    --- a/tools/include/uapi/linux/perf_event.h
    +++ b/tools/include/uapi/linux/perf_event.h
    @@ -1310,7 +1310,7 @@ union perf_mem_data_src {
    #define PERF_MEM_SNOOP_SHIFT 19

    #define PERF_MEM_SNOOPX_FWD 0x01 /* forward */
    -/* 1 free */
    +#define PERF_MEM_SNOOPX_PEER 0x02 /* xfer from peer */
    #define PERF_MEM_SNOOPX_SHIFT 38

    /* locked instruction */
    --
    2.32.0
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