[openstack-dev] [puppet] [tripleo] Host configuration for CPUAffinity and IRQ Pinning

Saravanan KR skramaja at redhat.com
Mon Aug 8 10:07:40 UTC 2016


For using DPDK, CPUs on compute host has to be isolated between Host,
DPDK PMD and Guests. In order, to configure the host to use only
specified CPUs, the CPUAffinity [1] configuration in
/etc/systemd/system.conf needs to be used. Along with CPUAffinity, IRQ
repining[2] needs to be done, to pin the interrupt requests to the
CPUs dedicated to host processes.

We are planning to do the changes for configuring CPUAffinity and IRQ
repining via puppet. We couldn't relate this configuration to any
existing module. Could you please help us with the direction to enable
these configurations?

Saravanan KR

Note: It is possible to use isolcpus via grub parameter, but it has
implications [3] on load balancing. So it is recommended to use
CPUAffinity to restrict CPUs for host process.

[1] https://www.freedesktop.org/software/systemd/man/systemd-system.conf.html#CPUAffinity=
[2] https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_MRG/1.3/html/Realtime_Tuning_Guide/sect-Realtime_Tuning_Guide-General_System_Tuning-Interrupt_and_Process_Binding.html
[3] https://lists.freedesktop.org/archives/systemd-devel/2016-July/037187.html

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