Messages in this thread | | | Date | Fri, 5 Nov 2021 12:56:09 +0100 | From | Paul Menzel <> | Subject | How to reduce PCI initialization from 5 s (1.5 s adding them to IOMMU groups) |
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Dear Linux folks,
On a PowerEdge T440/021KCD, BIOS 2.11.2 04/22/2021, Linux 5.10.70 takes almost five seconds to initialize PCI. According to the timestamps, 1.5 s are from assigning the PCI devices to the 142 IOMMU groups.
``` $ lspci | wc -l 281 $ dmesg […] [ 2.918411] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 2.933841] ACPI: Enabled 5 GPEs in block 00 to 7F [ 2.973739] ACPI: PCI Root Bridge [PC00] (domain 0000 [bus 00-16]) [ 2.980398] acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI HPX-Type3] [ 2.989457] acpi PNP0A08:00: _OSC: platform does not support [LTR] [ 2.995451] acpi PNP0A08:00: _OSC: OS now controls [PME PCIeCapability] [ 3.001394] acpi PNP0A08:00: FADT indicates ASPM is unsupported, using BIOS configuration [ 3.010511] PCI host bridge to bus 0000:00 […] [ 6.233508] system 00:05: [io 0x1000-0x10fe] has been reserved [ 6.239420] system 00:05: Plug and Play ACPI device, IDs PNP0c02 (active) [ 6.239906] pnp: PnP ACPI: found 6 devices […] [ 6.989016] pci 0000:d7:05.0: disabled boot interrupts on device [8086:2034] [ 6.996063] PCI: CLS 0 bytes, default 64 [ 7.000008] Trying to unpack rootfs image as initramfs... [ 7.065281] Freeing initrd memory: 5136K […] [ 7.079098] DMAR: dmar7: Using Queued invalidation [ 7.083983] pci 0000:00:00.0: Adding to iommu group 0 […] [ 8.537808] pci 0000:d7:17.1: Adding to iommu group 141 [ 8.571191] DMAR: Intel(R) Virtualization Technology for Directed I/O [ 8.577618] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) […] ```
Is there anything that could be done to reduce the time?
Kind regards,
Paul
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