[PATCH v4 4/4] docs: perf: Update metric usage for Alibaba's T-Head PMU driver

[Jing Zhang]

Alibaba's T-Head ali_drw PMU supports DDR bandwidth metrics. Update
its usage in the documentation.

Signed-off-by: Jing Zhang <renyu.zj at linux.alibaba.com>
Acked-by: Ian Rogers <irogers at google.com>
---
 Documentation/admin-guide/perf/alibaba_pmu.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/admin-guide/perf/alibaba_pmu.rst b/Documentation/admin-guide/perf/alibaba_pmu.rst
index 11de998..7d84002 100644
--- a/Documentation/admin-guide/perf/alibaba_pmu.rst
+++ b/Documentation/admin-guide/perf/alibaba_pmu.rst
@@ -88,6 +88,11 @@ data bandwidth::
     -e ali_drw_27080/hif_rmw/ \
     -e ali_drw_27080/cycle/ -- sleep 10
 
+Example usage of counting all memory read/write bandwidth by metric::
+
+  perf stat -M ddr_read_bandwidth.all -- sleep 10
+  perf stat -M ddr_write_bandwidth.all -- sleep 10
+
 The average DRAM bandwidth can be calculated as follows:
 
 - Read Bandwidth =  perf_hif_rd * DDRC_WIDTH * DDRC_Freq / DDRC_Cycle
-- 
1.8.3.1