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Subject[PATCH v7] perf: Add SNOOP_PEER flag to perf mem data struct
Date
From: Ali Saidi <alisaidi@amazon.com>

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.

Update notes:

This patch is to sync the headers between kernel and user space, commit
2e21bcf0514a ("perf tools: Sync addition of PERF_MEM_SNOOPX_PEER") for
updating kernel header has been merged in the mainline code.

Signed-off-by: Ali Saidi <alisaidi@amazon.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---

Changes from v6:
Added Leo's SoB.

include/uapi/linux/perf_event.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 03b370062741..581ed4bdc062 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -1313,7 +1313,7 @@ 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 */
--
2.34.1
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