AM69: How to interpret the PCIe benchmark data

Tony Tang

Part Number: AM69
Other Parts Discussed in Thread: TDA4VH,

I want to compare TI test data vs customer test data.

There is not header of each colum, how to interpret the data?

https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-j784s4/09_02_00_05/exports/docs/devices/J7_Family/linux/Release_Specific_Performance_Guide.html?highlight=benchmark#pcie-driver

over 2 years ago

0 Parth Nagpal over 2 years ago

TI__Mastermind 42135 points

Hi,

The assigned engineer is on business travel till Apr-18. Please expect a delay in response till then

Regards,
Parth

0 Takuma Fujiwara over 2 years ago in reply to Parth Nagpal

TI__Guru 61773 points

Hi Tony,

Thanks for letting us know about this. It seems the SDK doc has some issues for 9.2 version. Please reference the 9.1 SDK docs for the headers: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-j784s4/09_01_00_06/exports/docs/devices/J7_Family/linux/Release_Specific_Performance_Guide.html

I will open up an internal ticket to fix the header issue. At the latest, it should be fixed in next release.

Regards,

Takuma

0 Tony Tang over 2 years ago in reply to Takuma Fujiwara

TI__Mastermind 30707 points

Hi Takuma,

I did not find TDA4VH/J784s4 PCIe benchmark data on SDK9.1 user guide. Can you help to provide it?

0 Takuma Fujiwara over 2 years ago in reply to Tony Tang

TI__Guru 61773 points

Hi Tony,

I've got some numbers from 8.6 SDK, which should be similar to 9.1 SDK numbers.

READ: bw=2421MiB/s (2538MB/s) for 4 lane
READ: bw=1528MiB/s (1603MB/s) for 2 lane

For a total of around 4GB/s for 6 lanes being used simultaneously. These were ran using a PCIe NVMe device with the command: fio --name=/run/media/nvme0n1/test-pcie-1 --size=10GB --ioengine=libaio --iodepth=4 --numjobs=1 --direct=1 --runtime=60 --time_based --bs=4M

Feel free to run this on your end or at the customer end to confirm numbers.

Regards,

Takuma

0 Tony Tang over 2 years ago in reply to Takuma Fujiwara

TI__Mastermind 30707 points

Hi Takuma,

do you mean you tested with SDK8.6 on TDA4VH-EVM? or data from SDk8.6 user guide?

Is there method/guide to test between two TDA4 board?

Can I understand the efficiency of 4 Lane is : 2421MB * 8 /4x8Gbps=2.421*8/32=60.525%?

Where is the code of test-pcie-1?

0 Takuma Fujiwara over 2 years ago in reply to Tony Tang

TI__Guru 61773 points

Hi Tony,

Yes, I have tested with SDK 8.6 on TDA4VH-EVM and this was between a TDA4VH-EVM communicating to NVMe SSD card connected via PCIe. The "fio" commandline tool is installed in default Linux SDK image and test-pcie-1 is simply the name of the file the fio is writing to nvme0n1 SSD card.

8Gbps is theoretical throughput, but practical efficiency is affected by overhead from additional header required by packets, DMA initialization, and packet size.

Regards,

Takuma

0 ?? ? over 2 years ago

Prodigy 30 points

Hi Takuma,

I checked the TDA4VH-EVM and found that it only has a PCIe M.2 interface with 2 lane. How can I verify 4 lane？

I want to verify PCIe 4-lane data on the SK-AM69 development board. Are there any relevant examples

0 Takuma Fujiwara over 2 years ago in reply to ?? ?

TI__Guru 61773 points

Hi,

On SK-AM69 board there is a standard PCIe card slot that supports 4xlanes. An adapter between M.2 and standard slot can be used to verify 4 lane performance.

Regards,

Takuma

0 Tony Tang over 2 years ago in reply to Takuma Fujiwara

TI__Mastermind 30707 points

Hi Takuma,

Customer setup 4Land PCIe test as the picture.

Got result <40% of PCIe3.0 max bandwidth

host -> device ：1.5GB/s

device -> host ：1.9GB/s

while test PCIe M.2 M key 2lane，got 50%~60% of PCIe3.0 max bandwidth

host->device: 1151 M/s

device->host: 1040 M/s

The 4Lane throughput is quite low, is it related to the physical connection? or software configuration? How can we know if it works in PCIe3.0, and 4 Lane mode already?

0 Takuma Fujiwara over 2 years ago in reply to Tony Tang

TI__Guru 61773 points

Hi Tony,

You can confirm how many lanes and what PCIe gen speed is being used by running /usr/sbin/lspci -vvv. This prints out the most verbose information about the PCIe connection. There should be a field that says how many lanes and speed each link is.

Regards,

Takuma

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AM69: How to interpret the PCIe benchmark data