> I note that IRQs 25 & 30 are still effectively pinned to CPU3, > despite the smp_aff setting. > > $ cat /proc/interrupts > CPU0 CPU1 CPU2 CPU3 > 0: 27 0 0 0 IO-APIC 2-edge timer > 8: 0 0 0 0 IO-APIC 8-edge rtc0 > 9: 0 4 0 0 IO-APIC 9-fasteoi acpi > 16: 0 25 0 0 IO-APIC 16-fasteoi ehci_hcd:usb1 > 18: 0 5 0 0 IO-APIC 18-fasteoi i801_smbus > 23: 0 0 29 0 IO-APIC 23-fasteoi ehci_hcd:usb2 > 24: 0 0 0 0 PCI-MSI-0000:00:1c.0 0-edge PCIe PME, pciehp > 25: 0 0 0 0 PCI-MSI-0000:00:1c.3 0-edge PCIe PME > 26: 23328 0 0 37250 PCI-MSI-0000:00:1f.2 0-edge ahci[0000:00:1f.2] > 27: 86091 0 0 0 PCI-MSI-0000:00:14.0 0-edge xhci_hcd > 28: 0 0 51308 0 PCI-MSIX-0000:02:00.0 0-edge enp2s0 > 29: 0 0 22 0 PCI-MSI-0000:00:16.0 0-edge mei_me > 30: 0 0 0 604 PCI-MSI-0000:00:1b.0 0-edge snd_hda_intel:card0 > 31: 198664 0 0 0 PCI-MSI-0000:00:02.0 0-edge i915 > 32: 0 631 0 0 PCI-MSI-0000:00:03.0 0-edge snd_hda_intel:card1 Many drivers are not isolcpus aware. At least the sound driver could be unloaded for you test I suppose. > Almost exactly 20 ms in excess. > Could this be a hint? > But there is absolutely NOTHING traced between 4606.628019 & 4606.811832. Ensure your clock source is working correctly and... > I guess either my time source is incorrect. > (Next slide in Frederic's guide) > OR there is something wonky going on inside CPU3. ...there is no SMI running on this CPU, and no power management running (also in the BIOS settings) > Looks like IRQs are not the issue here? IRQ handling should be visible in the trace.
