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From: Mete Durlu <meted@linux.ibm.com>
To: kzak@redhat.com
Cc: util-linux@vger.kernel.org, hca@linux.ibm.com
Subject: [PATCH 2/2] chcpu(8): Document CPU deconfiguring behavior
Date: Mon,  2 Sep 2024 17:05:53 +0200	[thread overview]
Message-ID: <20240902150553.1969571-3-meted@linux.ibm.com> (raw)
In-Reply-To: <20240902150553.1969571-1-meted@linux.ibm.com>

If architecture supports (de)configuring CPUs, the user should
deconfigure disabled CPUs to prevent performance penalties.

Signed-off-by: Mete Durlu <meted@linux.ibm.com>
---
 sys-utils/chcpu.8.adoc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys-utils/chcpu.8.adoc b/sys-utils/chcpu.8.adoc
index 0b0bcbc57..f08b5a6ab 100644
--- a/sys-utils/chcpu.8.adoc
+++ b/sys-utils/chcpu.8.adoc
@@ -39,6 +39,8 @@ Enable the specified CPUs. Enabling a CPU means that the kernel sets it online.
 Deconfigure the specified CPUs. Deconfiguring a CPU means that the hypervisor removes the CPU from the virtual hardware on which the Linux instance runs and returns it to the CPU pool. A CPU must be offline, see *-d*, before it can be deconfigured.
 +
 *chcpu -g* is not supported on IBM z/VM, CPUs are always in a configured state.
++
+if *chcpu -g* is supported, any *disabled* CPUs should be *deconfigured* to inform the hypervisor that these CPUs won't be used, avoiding potential performance penalties.
 
 *-p*, *--dispatch* _mode_::
 Set the CPU dispatching _mode_ (polarization). This option has an effect only if your hardware architecture and hypervisor support CPU polarization. Available _modes_ are:
-- 
2.46.0


  parent reply	other threads:[~2024-09-02 15:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-02 15:05 [PATCH 0/2] chcpu documentation update Mete Durlu
2024-09-02 15:05 ` [PATCH 1/2] chcpu(8): Fix typo Mete Durlu
2024-09-02 15:05 ` Mete Durlu [this message]
2024-09-03  9:51 ` [PATCH 0/2] chcpu documentation update Karel Zak

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