From 35b8a1cae997efc51a3669b6e06393110de70d1c Mon Sep 17 00:00:00 2001 From: Balazs Gibizer Date: Tue, 7 Oct 2025 15:14:50 +0200 Subject: [PATCH] [doc]PCI in Placement tuning Related-Bug: #2070257 Related-Bug: #2126751 Change-Id: I602c78e02d1821fab202a91fc4e42e1b0cae42ad Signed-off-by: Balazs Gibizer --- doc/source/admin/pci-passthrough.rst | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/doc/source/admin/pci-passthrough.rst b/doc/source/admin/pci-passthrough.rst index 1ef1d7da79..b7ea69fd93 100644 --- a/doc/source/admin/pci-passthrough.rst +++ b/doc/source/admin/pci-passthrough.rst @@ -393,6 +393,15 @@ PCI tracking in Placement Please note that once it is enabled on a given compute host **it cannot be disabled there any more**. +.. warning:: + If you configure more than 8 PCI devices per compute with the same + product_id or resource_class then placement needs configuration tuning + to keep the scheduling speed acceptable. Please read the following + two release notes: + + * https://github.com/openstack/placement/blob/master/releasenotes/notes/bug-2070257-allocation-candidates-generation-limit-and-strategy.yaml-e73796898163fb55.yaml + * https://github.com/openstack/placement/blob/master/releasenotes/notes/bug-2126751-optimize_for_wide_provider_trees-b50b7813fd0d9dd2.yaml + Since nova 26.0.0 (Zed) PCI passthrough device inventories are tracked in Placement. If a PCI device exists on the hypervisor and matches one of the device specifications configured via