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>
Reviewed-by: Chris Healy <healych@xxxxxxxxxx>
---
Changes v10 -> v11:
- Reword perf documentation
Changes v9 -> v10:
- Rebase code
- Add "Reviewed-by" tag
Changes v8 -> v9:
- No change
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 793e1970bc05..c767e03e4d34 100644
--- a/Documentation/admin-guide/perf/index.rst
+++ b/Documentation/admin-guide/perf/index.rst
@@ -19,3 +19,4 @@ Performance monitor support
arm_dsu_pmu
thunderx2-pmu
alibaba_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..8e71be1d6346
--- /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)
+===========================================================
+
+The Amlogic Meson G12 SoC contains a bandwidth monitor inside DRAM controller.
+The monitor includes 4 channels. Each channel can count the request accessing
+DRAM. The channel can count up to 3 AXI port simultaneously. 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 channel-specific events.
+Each channel support filtering, which can let the channel to monitor
+individual IP module in SoC.
+
+Below are DDR access request event filter keywords:
+
++ arm - from CPU
++ vpu_read1 - from OSD + VPP read
++ gpu - from 3D GPU
++ pcie - from PCIe controller
++ hdcp - from HDCP controller
++ hevc_front - from HEVC codec front end
++ usb3_0 - from USB3.0 controller
++ hevc_back - from HEVC codec back end
++ h265enc - from HEVC encoder
++ vpu_read2 - from DI read
++ vpu_write1 - from VDIN write
++ vpu_write2 - from di write
++ vdec - from legacy codec video decoder
++ hcodec - from H264 encoder
++ ge2d - from ge2d
++ spicc1 - from SPI controller 1
++ usb0 - from USB2.0 controller 0
++ dma - from system DMA controller 1
++ arb0 - from arb0
++ sd_emmc_b - from SD eMMC b controller
++ usb1 - from USB2.0 controller 1
++ audio - from Audio module
++ sd_emmc_c - from SD eMMC c controller
++ spicc2 - from SPI controller 2
++ ethernet - from Ethernet controller
+
+
+Examples:
+
+ + Show the total DDR bandwidth per seconds:
+
+ .. code-block:: bash
+
+ perf stat -a -e meson_ddr_bw/total_rw_bytes/ -I 1000 sleep 10
+
+
+ + Show individual DDR bandwidth from CPU and GPU respectively, as well as
+ sum of them:
+
+ .. 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
+
diff --git a/MAINTAINERS b/MAINTAINERS
index 415eaa30c523..b76c4deddf22 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1098,6 +1098,7 @@ 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
