TX2 JetPack 4.6 memory bandwidth has dropped

Hi everyone,

I use TX2 module intalled JetPack 4.6. I use mbw test memory bandwidth, the bandwidth has dropped. The mbw source code GitHub - raas/mbw: Memory Bandwidth Benchmark
Before I test I maximize the performance first

$ sudo nvpmodel -m 0
$ sudo jetson_clocks

TX2 intall JetPack 4.3 test result

./mbw -q -n 10 256
AVG     Method: MEMCPY  Elapsed: 0.03210        MiB: 256.00000  Copy: 7975.277 MiB/s
AVG     Method: DUMB    Elapsed: 0.05566        MiB: 256.00000  Copy: 4599.535 MiB/s
AVG     Method: MCBLOCK Elapsed: 0.04334        MiB: 256.00000  Copy: 5906.456 MiB/s

TX2 intall JetPack 4.6test result

./mbw -q -n 10 256
AVG     Method: MEMCPY  Elapsed: 0.06929        MiB: 256.00000  Copy: 3694.862 MiB/s
AVG     Method: DUMB    Elapsed: 0.26994        MiB: 256.00000  Copy: 948.359 MiB/s
AVG     Method: MCBLOCK Elapsed: 0.06397        MiB: 256.00000  Copy: 4002.139 MiB/s

When testing I check the EMC_FREQ as below

$ sudo tegrastats 
RAM 1552/7860MB (lfb 1287x4MB) SWAP 0/3930MB (cached 0MB) CPU [100%@2035,0%@2035,0%@2035,0%@2049,0%@2054,0%@2035] EMC_FREQ 14%@1866 GR3D_FREQ 0%@1300 APE 150 MTS fg 0% bg 0% PLL@46C MCPU@46C PMIC@50C Tboard@41C GPU@44.5C BCPU@46C thermal@45.4C Tdiode@44.75C VDD_SYS_GPU 228/228 VDD_SYS_SOC 1068/1035 VDD_4V0_WIFI 0/0 VDD_IN 5268/4994 VDD_SYS_CPU 1221/1100 VDD_SYS_DDR 1692/1608

What’s diffrence between JetPack 4.6 and JetPack 4.3? Thanks.

Hi kenny_234,

Can you try ‘iozone3’ tool to test memory read/write bandwidth?

sudo apt update
sudo apt install iozone3
sudo jetson_clocks

Hi carolyuu,
Iozone is a filesystem benchmark tool, we need test memory bandwidth. Could you use mbw tool test memory bandwidth?

Hi kenny_234,

I can see the same result.
We will check this issue and update to you.

Hi kenny_234,

Please remove isolcpus=1-2 in kernel cmdline with ‘p2771-000.conf.common’ file and try again.
Thanks!

HIi carolyuu,
Thank you for your reply, the memory bandwidth is improved.

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