The event type 'ldst' is added for recording both load and store memory
operations, this patch documents for the new event type.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 tools/perf/Documentation/perf-mem.txt | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt
index 199ea0f0a6c0..c50ef37dba72 100644
--- a/tools/perf/Documentation/perf-mem.txt
+++ b/tools/perf/Documentation/perf-mem.txt
@@ -38,7 +38,11 @@ OPTIONS
 
 -t::
 --type=<type>::
-	Select the memory operation type: load or store (default: load,store)
+	Select the memory operation type: load, store, ldst (default: load,store).
+	The type 'ldst' means the single event can record both for load and store
+	operations; Intel and PowerPC support the types 'load' and 'store' but
+	'ldst' cannot be used; on Arm64, it uses Arm SPE as memory events and
+	user needs to specify one of these three types.
 
 -D::
 --dump-raw-samples::
-- 
2.17.1