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:
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:
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