realtime patch for xavier kernel

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

hi,
Do you have realtime patch for xavier kernel ？ Thank you！

2

Hi Jason_888,

Please refer to [url]rt patch in jetpack 4.2.1 - Jetson AGX Xavier - NVIDIA Developer Forums

1 Like
3

Hi kayccc,
Thank you for your reply！
I have refered to the link ,and I patch the rt-patch follow the instruction below.

./scripts/rt-patch.sh apply-patches

then I build the kernel,no errors

cd kernel/kernel-4.9/
make O=$TEGRA_KERNEL_OUT zImage
make O=$TEGRA_KERNEL_OUT dtbs

then I flash the kernel and dtb to the board

cd Linux_for_Tegra/
sudo ./flash.sh jetson-xavier mmcblk0p1

after I flash the kernel and dtb then I reboot the board and I find we can not boot the board attachment is the boot log.
bootlog.txt (100 KB)

4

Could you attached the Image and DTB to verify.

5

hi ShaneCCC,
When I use the new version R32.2.1,the rt patch can work .

uname -a                                                 
Linux mystique 4.9.140-rt94

But there are some other problems ，I find hdmi ,pcie ,mipi camera can not work normally,this module can work normally befor patch the rt-patchs.

below is the dtb and image

dtb-image.zip (10.3 MB)

6

Hi Jason,

Did you copy over the built modules to /lib/modules/uname -r/ on the system?

7

@Jason
Due the kernel name is different after rt patch you need copy the new module to the device as Anish.aney said.

8

Hi anish.aney ,ShaneCCC
It is very helpful, thank you! Our xavier board can work now.
But Hdmi screen looks blurry,I adjust the resolution ,it seems make not work.
Another question is about jetson_clocks，when I execute command “jetson_clocks”,I got the error below:

jetson_clocks 
[sudo] password for nvidia: 
/usr/bin/jetson_clocks: line 233: /sys/devices/system/cpu/cpu[0-9]/cpuidle/state[0-9]/disable: No such file or directory
9

Hello,

That’s because the ./rt-patch.sh script disables “CPU_IDLE_TEGRA19X” config option.
Even if you see this message, I think you can ignore it. jetson_clocks --show should show the frequencies updated to correct values depending on the nvpmodel mode.

10

Hi AnishAney，
Thank you for your explain！
Another problem is that I find RT kernel boot time is 30sec longer than normal kernel.Have you seen this situation on your xavier?

11

Hello Jason,

Yes, I just ran RedHawk kernels w/ and w/o PREEMPT_RT patch, and saw a difference of 10-12sec during boot time while booting our tracing-only flavor and a 23-25sec while booting kernels having all the debug features enabled.

A tracing-only kernel is best for ensuring RT performance.
A debug feature enabled kernel is best for debugging device drivers during its development phase.

I have not looked at the differences closely but will try to do that.

12

Hi pablo,
Do you know how to speed up boot time in RT patch kernel？
And how to close the debug feature you said？

13

Hello Jason,

Pablo is a colleague.

Our product has 6 “flavors” of RedHawk kernel; debug(all debug features enabled), trace(debug featured turned off and our minimal tracing) and standard(no debug and tracing feature), and the PREEMPT_RT enabled versions of these.

The difference in timing that he mentioned was between these flavors and their PREEMPT_RT counterpart. We have not looked at speeding up the boot time.

14

AnishAney，
I see ,thank you !