I am using EtherCAT fieldbus on Raspberry Pi 4B. It has high requirements for real-time network communication.
I was based on the rpi-6.1.21 64 bit kernel.Then I patched the PREEMPT_RT patch named patch-6.1.26-rt8.patch, which could be downloaded here and activated “Fully Preemptible Kernel (Real-Time)” option.
After using the new kernel, query the kernel version as 6.1.21-rt8-v8+.I used stress-ng and cyclictest tools for testing, and compared the performance of no-PREEMPT_RT patched kernel with those that were patched PREEMPT_RT.
Test Command：The result without PREEMPT_RT patched：The result with PREEMPT_RT patched：In addition, I disable the power saving modes in the kernel and scheduling governors.Most of the time, the real-time jitter is relatively stable, but after running for a period of time (possibly several tens of minutes), the jitter will suddenly increase.
Therefore, I would like to know if there are any real-time optimizations for network drivers or file system？
I was based on the rpi-6.1.21 64 bit kernel.Then I patched the PREEMPT_RT patch named patch-6.1.26-rt8.patch, which could be downloaded here and activated “Fully Preemptible Kernel (Real-Time)” option.
After using the new kernel, query the kernel version as 6.1.21-rt8-v8+.
Test Command：
Code:
stress-ng --cpu 6 --io 4 --vm 2 --cpu-method allsudo cyclictest -t 6 -p 80Code:
policy: fifo: loadavg: 15.42 13.11 7.19 2/183 10012T: 0 ( 4348) P:80 I:1000 C: 569122 Min: 6 Act: 18 Avg: 35 Max: 683T: 1 ( 4349) P:80 I:1500 C: 379415 Min: 6 Act: 12 Avg: 30 Max: 594T: 2 ( 4350) P:80 I:2000 C: 284561 Min: 6 Act: 10 Avg: 26 Max: 570T: 3 ( 4351) P:80 I:2500 C: 227648 Min: 8 Act: 10 Avg: 27 Max: 453T: 4 ( 4352) P:80 I:3000 C: 189707 Min: 8 Act: 16 Avg: 22 Max: 511T: 5 ( 4353) P:80 I:3500 C: 162606 Min: 7 Act: 10 Avg: 35 Max: 484Code:
policy: fifo: loadavg: 11.39 11.45 9.24 1/386 1986T: 0 ( 1880) P:80 I:1000 C:1003821 Min: 6 Act: 7 Avg: 22 Max: 230T: 1 ( 1881) P:80 I:1500 C: 669214 Min: 6 Act: 7 Avg: 20 Max: 207T: 2 ( 1882) P:80 I:2000 C: 501910 Min: 7 Act: 10 Avg: 19 Max: 158T: 3 ( 1883) P:80 I:2500 C: 401528 Min: 8 Act: 9 Avg: 19 Max: 129T: 4 ( 1884) P:80 I:3000 C: 334607 Min: 7 Act: 10 Avg: 19 Max: 248T: 5 ( 1885) P:80 I:3500 C: 286806 Min: 7 Act: 11 Avg: 25 Max: 215Code:
sudo sh -c "echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor"Therefore, I would like to know if there are any real-time optimizations for network drivers or file system？
Statistics: Posted by FrankLee — Tue Jan 16, 2024 8:43 am