From 343c06ff7617ac32b45bde348ca6ec5533c5d95a Mon Sep 17 00:00:00 2001 From: Ron Stone Date: Fri, 7 Oct 2022 11:12:11 -0400 Subject: [PATCH] Stale SMT information (r7,dsR7) Update description of hyperthreading behavior in r7. Signed-off-by: Ron Stone Change-Id: I4d036c15f14566c4b55ec82208eb56715e2aa07b --- ...-cores-to-enhance-application-performance.rst | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/doc/source/admintasks/kubernetes/isolating-cpu-cores-to-enhance-application-performance.rst b/doc/source/admintasks/kubernetes/isolating-cpu-cores-to-enhance-application-performance.rst index febe4fd19..72118810f 100644 --- a/doc/source/admintasks/kubernetes/isolating-cpu-cores-to-enhance-application-performance.rst +++ b/doc/source/admintasks/kubernetes/isolating-cpu-cores-to-enhance-application-performance.rst @@ -35,14 +35,16 @@ The use of application-isolated cores is only applicable when using the static Kubernetes CPU Manager policy. For more information, see :ref:`Kubernetes CPU Manager Policies `. -**Limitation**: If Hyperthreading is enabled in the BIOS and -application-isolated CPUs are configured, and these CPUs are allocated to more -than one container, the |SMT| siblings may be allocated to different containers -and that could adversely impact the performance of the application. +.. note:: -**Workaround**: The suggested workaround is to allocate all -application-isolated CPUs on a host to a single pod. For more information, see -Node Management: :ref:`Changing the Hyper-threading Status `. + |prod| isolcpus allocation is |SMT|-aware. If a container requests multiple + isolcpus it will provide |SMT| siblings to the extent possible. If an odd + number of isolcpus are requested it will provide as many |SMT| siblings as + are available, then allocate singletons whose sibling has already been + allocated, then allocate one sibling from a free |SMT| sibling pair. If + hyperthreading is enabled in the BIOS then containers should request isolcpus + in pairs. If all containers on a system do this then they will never have + different containers being allocated |SMT| siblings from the same core. When using the static CPU manager policy before increasing the number of platform CPUs or changing isolated CPUs to application CPUs on a host, ensure