Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Nathan Lynch <nathanl@linux.ibm.com>
To:     Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
        Kamalesh Babulal <kamaleshb@in.ibm.com>,
        "Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Tyrel Datwyler <tyreld@linux.ibm.com>
Subject: Re: [PATCH 0/2] pseries/hotplug: Change the default behaviour of cede_offline
In-Reply-To: <20190918123039.GA12534@in.ibm.com>
References: <1568284541-15169-1-git-send-email-ego@linux.vnet.ibm.com> <87impxr0am.fsf@linux.ibm.com> <20190915074217.GA943@in.ibm.com> <87a7b2rfj0.fsf@linux.ibm.com> <20190918123039.GA12534@in.ibm.com>
Date:   Wed, 18 Sep 2019 12:08:43 -0500
Message-ID: <874l19r0pw.fsf@linux.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Gautham R Shenoy <ego@linux.vnet.ibm.com> writes:
> The accounting problem in tools such as lparstat with
> "cede_offline=on" is affecting customers who are using these tools for
> capacity-planning. That problem needs a fix in the short-term, for
> which Patch 1 changes the default behaviour of cede_offline from "on"
> to "off". Since this patch would break the existing userspace tools
> that use the CPU-Offline infrastructure to fold CPUs for saving power,
> the sysfs interface allowing a runtime change of cede_offline_enabled
> was provided to enable these userspace tools to cope with minimal
> change.

So we would be putting users in the position of choosing between folding
and correct accounting. :-(

Actually how does changing the offline mechanism to stop-self break the
folding utility?