perf tools: Sync addition of PERF_MEM_SNOOPX_PEER

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.

Committer notes:

This really is not syncing with the kernel since the patch to the kernel
wasn't merged.

But we're going ahead of this as it seems trivial and is just a matter
of the perf kernel maintainers to give their ack or for us to find
another way of expressing this in the perf records synthesized in
userspace from the ARM64 hardware traces.

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Ali Saidi <alisaidi@amazon.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Like Xu <likexu@tencent.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Timothy Hayes <timothy.hayes@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20220811062451.435810-2-leo.yan@linaro.org
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index 4653834..e2b77fb 100644 (file)
--- 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 */