How to isolate a processor from a running system ? (Doc ID 1012392.1)

Last updated on SEPTEMBER 05, 2023

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Goal

There are several ways to "remove" a processor from a running system but these operations have different goals and different consequences.

Processor isolation can be done by changing the operational status of a processor. To achieve that goal, a processor can be off-line or unconfigured.

The aim of this document is to present the differences between psradm -f, psradm -i and cfgadm -c unconfigure for the UltraSparc II, UltraSparc ( III, IV,  IV+ ) and SPARC64 ( VI,VII, VII+ ) processors. This document provides an overview of the different ways to isolate a cpu from a running system on various SPARC CPUs.

Using the appropriate status and the appropriate command can be very useful in many cases: troubleshooting, performances analysis and so on .. For example, a cpu can be offlined to see if that cpu has any role in a transient hardware failure. Once a cpu is confirmed to have a hardware issue, it can be isolated using cfgadm. A cpu can be dedicated to processing just user level/system level threads and isolated from processing interrupts. Depending on what one needs, these commands can be effectively used.

Solution