I applied real-time kernel to Raspberry Pi cm4.
Linux raspberrypi 5.10.110-rt65-v7l_RT_NOHZ+ #1 SMP PREEMPT_RT Fri Jan 17 00:45:16 GMT 2025 armv7l GNU/Linux
The options I tested were:
isolcpus=2,3 nohz_full=2,3 rcu_nocbs=2,3 Linux.DisableCpuDmaLatency=1 irqaffinity=0,1
/proc/sys/kernel/sched_rt_runtime_us = -1
The task was set to FIFO
The cores are isolated and only tasks that are to be used in real time are assigned to the cores.
The clock speed is fixed at 1.5GHz and cooling is sufficient.
Just in case, the process priority was also set to -60.
When performing the task, jitter is introduced.
A task that operates at an average of 400 microseconds experiences cycles of up to 2000 microseconds.
However, if the `maxcpus` option is set to 1 and runs on a single core, jitter does not occur.
Is there any solution?
Linux raspberrypi 5.10.110-rt65-v7l_RT_NOHZ+ #1 SMP PREEMPT_RT Fri Jan 17 00:45:16 GMT 2025 armv7l GNU/Linux
The options I tested were:
isolcpus=2,3 nohz_full=2,3 rcu_nocbs=2,3 Linux.DisableCpuDmaLatency=1 irqaffinity=0,1
/proc/sys/kernel/sched_rt_runtime_us = -1
The task was set to FIFO
The cores are isolated and only tasks that are to be used in real time are assigned to the cores.
The clock speed is fixed at 1.5GHz and cooling is sufficient.
Just in case, the process priority was also set to -60.
When performing the task, jitter is introduced.
A task that operates at an average of 400 microseconds experiences cycles of up to 2000 microseconds.
However, if the `maxcpus` option is set to 1 and runs on a single core, jitter does not occur.
Is there any solution?
Statistics: Posted by yhyoon — Wed Jan 22, 2025 12:49 am