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Fri, 09 Jan 2026 11:09:07 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/21503 Hi Pavel, On 1/9/26 10:58, Pavel Machek via lists.cip-project.org wrote: > Hi! >=20 >> has anyone already tested preempt_rt on the BeagleV-Fire? >> >> OSADL has evaluated preempt_rt on both the PolarFire Icicle Kit >> (MPFS250T) and the PolarFire Discovery Kit (MPFS095T) and has reported >> rather problematic latency results so far[1]. >> >> Since the BeagleV-Fire is also based on a PolarFire SoC (MPFS025T), I >> suspect we might run into similar issues. Any experiences, measurements, >> or insights would be greatly appreciated. >=20 > Those OSADL results actually look good to me :-). >=20 > Ok, so let me explain. BeagleV-Fire seems to have slow CPUs. Like > "Nokia N900" slow. That's TI OMAP 3430 SoC, 600 MHz ARM Cortex-A8 CPU > from 2010 or so. >=20 > It is certainly less than 10% of speed of Core i9-9900K, and that one > reaches 100usec... >=20 > https://www.osadl.org/Latency-plot-of-system-in-rack-0-slot.qa-latencyplo= t-r0s5.0.html?latencies=3D&showno=3D&shadow=3D1&slider=3D360 >=20 > ...so 350usec is actually not that bad, AFAICT. I cannot see any CPU isolation in the profile data for the Core=20 i9-9900K. Maybe they are using cgroups here, and this is not visible. Comparing the isolated cores of the VisionFive2 @ 1500 MHz [1] to the=20 MPFS250T @ 600 MHz [2], it is more like 45 =C2=B5s to 250 =C2=B5s. Your point is still valid. The gap may not be as large as it looks at=20 first glance, but I don=E2=80=99t think the difference in frequency explain= s it=20 completely. Best, Tobias [1]=20 https://www.osadl.org/Latency-plot-of-system-in-rack-3-slot.qa-latencyplot-= r3s2.0.html?shadow=3D1 [2]=20 https://www.osadl.org/Latency-plot-of-system-in-rack-7-slot.qa-latencyplot-= r7s2.0.html?shadow=3D1 > Not sure what our requirements are, sometimes people put the > time-critical stuff into FPGA. >=20 > Best regards, > Pavel >=20 >=20 >=20 > -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- > Links: You receive all messages sent to this group. > View/Reply Online (#21493): https://lists.cip-project.org/g/cip-dev/messa= ge/21493 > Mute This Topic: https://lists.cip-project.org/mt/117149606/7247900 > Group Owner: cip-dev+owner@lists.cip-project.org > Unsubscribe: https://lists.cip-project.org/g/cip-dev/unsub [tobias.schaff= ner@siemens.com] > -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- >=20