linux-kernel - Re: [PATCH] cpuidle/powernv : init all present cpus for deep states

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Message-Id: <87efiby6a9.fsf@linux.vnet.ibm.com>
Date:   Wed, 16 May 2018 10:22:22 -0500
From:   Stewart Smith <stewart@...ux.ibm.com>
To:     Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Cc:     Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>, npiggin@...il.com,
        ego@...ux.vnet.ibm.com
Subject: Re: [PATCH] cpuidle/powernv : init all present cpus for deep states

Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com> writes:
> Init all present cpus for deep states instead of "all possible" cpus.
> Init fails if the possible cpu is gaurded. Resulting in making only
> non-deep states available for cpuidle/hotplug.

Should this also head to stable? It means that for single threaded
workloads, if you guard out a CPU core you'll not get WoF, which means
that performance goes down when you wouldn't expect it to. Right?

-- 
Stewart Smith
OPAL Architect, IBM.