Add a user guide to show how to use DDR PMU to
monitor DDR bandwidth on Amlogic G12 SoC
Signed-off-by: Jiucheng Xu <jiucheng.xu@xxxxxxxxxxx>
---
Changes v7 -> v8:
- No change
Changes v6 -> v7:
- Drop the Reported-by tag
- Fix spelling error
Changes v5 -> v6:
- No change
Changes v4 -> v5:
- Fix building warning
Changes v3 -> v4:
- No change
Changes v2 -> v3:
- Rename doc name from aml-ddr-pmu.rst to meson-ddr-pmu.rst
Changes v1 -> v2:
- Nothing was changed
---
Documentation/admin-guide/perf/index.rst | 1 +
.../admin-guide/perf/meson-ddr-pmu.rst | 70 +++++++++++++++++++
MAINTAINERS | 1 +
3 files changed, 72 insertions(+)
create mode 100644 Documentation/admin-guide/perf/meson-ddr-pmu.rst
diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst
index 69b23f087c05..997a28e156c1 100644
--- a/Documentation/admin-guide/perf/index.rst
+++ b/Documentation/admin-guide/perf/index.rst
@@ -17,3 +17,4 @@ Performance monitor support
xgene-pmu
arm_dsu_pmu
thunderx2-pmu
+ meson-ddr-pmu
diff --git a/Documentation/admin-guide/perf/meson-ddr-pmu.rst b/Documentation/admin-guide/perf/meson-ddr-pmu.rst
new file mode 100644
index 000000000000..15e93a751ced
--- /dev/null
+++ b/Documentation/admin-guide/perf/meson-ddr-pmu.rst
@@ -0,0 +1,70 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================================================
+Amlogic SoC DDR Bandwidth Performance Monitoring Unit (PMU)
+===========================================================
+
+There is a bandwidth monitor inside the DRAM controller. The monitor includes
+4 channels which can count the read/write request of accessing DRAM individually.
+It can be helpful to show if the performance bottleneck is on DDR bandwidth.
+
+Currently, this driver supports the following 5 Perf events:
+
++ meson_ddr_bw/total_rw_bytes/
++ meson_ddr_bw/chan_1_rw_bytes/
++ meson_ddr_bw/chan_2_rw_bytes/
++ meson_ddr_bw/chan_3_rw_bytes/
++ meson_ddr_bw/chan_4_rw_bytes/
+
+meson_ddr_bw/chan_{1,2,3,4}_rw_bytes/ events are the channel related events.
+Each channel support using keywords as filter, which can let the channel
+to monitor the individual IP module in SoC.
+
+The following keywords are the filter:
+
++ arm - DDR access request from CPU
++ vpu_read1 - DDR access request from OSD + VPP read
++ gpu - DDR access request from 3D GPU
++ pcie - DDR access request from PCIe controller
++ hdcp - DDR access request from HDCP controller
++ hevc_front - DDR access request from HEVC codec front end
++ usb3_0 - DDR access request from USB3.0 controller
++ hevc_back - DDR access request from HEVC codec back end
++ h265enc - DDR access request from HEVC encoder
++ vpu_read2 - DDR access request from DI read
++ vpu_write1 - DDR access request from VDIN write
++ vpu_write2 - DDR access request from di write
++ vdec - DDR access request from legacy codec video decoder
++ hcodec - DDR access request from H264 encoder
++ ge2d - DDR access request from ge2d
++ spicc1 - DDR access request from SPI controller 1
++ usb0 - DDR access request from USB2.0 controller 0
++ dma - DDR access request from system DMA controller 1
++ arb0 - DDR access request from arb0
++ sd_emmc_b - DDR access request from SD eMMC b controller
++ usb1 - DDR access request from USB2.0 controller 1
++ audio - DDR access request from Audio module
++ sd_emmc_c - DDR access request from SD eMMC c controller
++ spicc2 - DDR access request from SPI controller 2
++ ethernet - DDR access request from Ethernet controller
+
+
+The following command is to show the total DDR bandwidth:
+
+ .. code-block:: bash
+
+ perf stat -a -e meson_ddr_bw/total_rw_bytes/ -I 1000 sleep 10
+
+This command will print the total DDR bandwidth per second.
+
+The following commands are to show how to use filter parameters:
+
+ .. code-block:: bash
+
+ perf stat -a -e meson_ddr_bw/chan_1_rw_bytes,arm=1/ -I 1000 sleep 10
+ perf stat -a -e meson_ddr_bw/chan_2_rw_bytes,gpu=1/ -I 1000 sleep 10
+ perf stat -a -e meson_ddr_bw/chan_3_rw_bytes,arm=1,gpu=1/ -I 1000 sleep 10
+
+The 1st command show how to use channel 1 to monitor the DDR bandwidth from ARM.
+The 2nd command show using channel 2 to get the DDR bandwidth of GPU.
+The 3rd command show using channel 3 to monitor the sum of ARM and GPU.
diff --git a/MAINTAINERS b/MAINTAINERS
index eb63b9cbc149..5ed563368a48 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1055,6 +1055,7 @@ M: Jiucheng Xu <jiucheng.xu@xxxxxxxxxxx>
L: linux-amlogic@xxxxxxxxxxxxxxxxxxx
S: Supported
W: http://www.amlogic.com
+F: Documentation/admin-guide/perf/meson-ddr-pmu.rst
F: drivers/perf/amlogic/
F: include/soc/amlogic/
--
2.25.1
