Hi, I am Burak. I am working on Jetson Orin Developer Kit which has Arm Cortex A78AE CPU. I am trying to take benchmark of PCIe transfer speed. But I encountered a strange situation. When I took benchmark of an PCIe Gen2 x4 port with Intel CPU, my graph is like attachment1(I
). I wonder why PCIe transfer speed of 2KB-4KB block sizes on Arm CPU is falling from 2GB/s to 200MB/s. Also, I couldn’t get near of theorical PCIe transfer speed, which is 4GB/s on PCIe Gen2 x8 port, but only half of it. I tried to debug this problem, and when I check “dmesg” command of Ubuntu OS, I saw many “arm-smmu: 12000000.iommu: Unhandled context fault: fsr=0x80000402, iova=0xffXXXXXX, fsynr=0x80013, cbfrsynra=0x1014, cb=6” messages. I can send all of this messages if you want.
I suspect that SMMU causes this transfer speed falling problem. Can you help me about that?
Hi,
Sorry for the missing information. I connected a FPGA via Gen2 x8 PCIe port of Developer Kit. FPGA supports only Gen2. I am writing data to Jetson’s RAM from FPGA. Jetson is RC and FPGA is endpoint. I am using RIFFA open source PCIe framework for FPGAs.
It means there is invalid memory access. Looks like there may be certain issue in the driver. Would suggest check this first. This print is not expected.
