Bad memory performance on JetPack 5.0.2 (5.10.104-tegra)

Memory performance has declined severely with the new kernel.

Could you please advice to kernel settings that restore performance to the JetPack 4.4.1 level (4.9.140-tegra)?

Performance comparison:
sudo mount tmpfs -ttmpfs -osize=4G /mnt/
sudo dd if=/dev/zero of=/mnt/zero.bin bs=1M count=4000

  • JP441: 4194304000 bytes (4.2 GB, 3.9 GiB) copied, 1.55166 s, 2.7 GB/s
  • JP502: 4194304000 bytes (4,2 GB, 3,9 GiB) copied, 3,9952 s, 1,0 GB/s

sudo dd if=/mnt/zero.bin of=/dev/null bs=1M

  • JP441: 4194304000 bytes (4.2 GB, 3.9 GiB) copied, 0.626467 s, 6.7 GB/s
  • JP502: 4194304000 bytes (4,2 GB, 3,9 GiB) copied, 0,76411 s, 5,5 GB/s

for OPER in write read; do sysbench --threads=$(nproc) --memory-oper=${OPER} memory run; done

  • JP441: 2271.58 MiB/sec / 20623.23 MiB/sec
  • JP502: 1869.11 MiB/sec / 12256.02 MiB/sec
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Could you boost clocks to try.

sudo nvpmodel -m 0
sudo jetson_clocks
sudo su
echo 1 > /sys/kernel/debug/bpmp/debug/clk/emc/mrq_rate_locked
cat /sys/kernel/debug/bpmp/debug/clk/emc/max_rate | tee /sys/kernel/debug/bpmp/debug/clk/emc/rate

No change at all unfortunatly.

Could you check if the emc clock with J4.x

cat /sys/kernel/debug/bpmp/debug/clk/emc/rate

It’s lower than for JP5.


$ sudo cat /sys/kernel/debug/bpmp/debug/clk/emc/max_rate
$ sudo cat /sys/kernel/debug/bpmp/debug/clk/emc/rate

Could you check the /etc/nvpmode.conf to confirm the select the Max power mode like


Yes, this is already verified to not be the culprit.
I’m running the same mode on both 4.1.1 and 5.0.2.

The 5.0.2 default configuration does not however contain all modes, so needed to add them manually.

Do you have any other suggestions?

I’ve tried running both kernels on the same rootfs, still get the poor performance on the jp5 kernel.
Everything points to a kernel problem, not a configuration problem.

Do you have any kernel settings to improve performance?

Do I have any attention here or do you ignore this?

1 Like

We try on different device get better performance on J5.0.2 than J4.x
Maybe need to get the result on the same XNX to check

Could you please send me your results? And information of how you get the result?

I’ve tried running the exact same module, and tried running over a family of 4, getting way lower performance on jp5 on all of them.

Could you please accept this issue and help working for a solution?

I again tried, this time on a brand new xavier nx devkit.
Same issue, about half the memory performance on JP502 compared to JP411.

If you have other experience you need to show some proof!