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SMI problem on AMD Epyc 7301

Question asked by f.popchenko on Jun 3, 2019
Latest reply on Jul 16, 2019 by djselbeck


I'm working with AMD Epyc 7301 (AMD64 Family 17h model 00h-0Fh) with QNX (real-time OS) and have SMI interruptions on all CPUs every 32 ms for ~400 us. But in Linux (SLES RT) i dont't see such behaviour and the SMI counter in MSR results 0. I've read Performance Tuning Guidelines for Low Latency Response on AMD EPYC™-Based Servers Application Note and perform all BIOS optimization to decrease or remove SMIs, but it didn't work in this case. 

So, I have some questions:

1. Is there a way to disable SMI or sources of SMI in MSR or other specific registers, that I can write from OS?

2. Do you have any suggestions what can be a reason for such behaviour?

3. In case if you known with this promlem, what should I do to reduse SMIs in QNX like it works in Linux?