From: Michael Ellerman <mpe@ellerman.id.au>
To: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Stewart Smith <stewart@linux.vnet.ibm.com>,
Michael Neuling <mikey@neuling.org>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>,
Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org,
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
Subject: Re: [PATCH] cpuidle:powernv: Make the snooze timeout dynamic.
Date: Mon, 04 Jun 2018 21:27:40 +1000 [thread overview]
Message-ID: <87fu22bxlf.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <1527768909-32637-1-git-send-email-ego@linux.vnet.ibm.com>
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com> writes:
> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> The commit 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of
> snooze to deeper idle state") introduced a timeout for the snooze idle
> state so that it could be eventually be promoted to a deeper idle
> state. The snooze timeout value is static and set to the target
> residency of the next idle state, which would train the cpuidle
> governor to pick the next idle state eventually.
>
> The unfortunate side-effect of this is that if the next idle state(s)
> is disabled, the CPU will forever remain in snooze, despite the fact
> that the system is completely idle, and other deeper idle states are
> available.
That sounds like a bug, I'll add?
Fixes: 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state")
Cc: stable@vger.kernel.org # v4.2+
cheers
next prev parent reply other threads:[~2018-06-04 11:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-31 12:15 [PATCH] cpuidle:powernv: Make the snooze timeout dynamic Gautham R. Shenoy
2018-05-31 14:51 ` Balbir Singh
2018-06-01 4:54 ` Gautham R Shenoy
2018-06-02 0:16 ` Balbir Singh
2018-06-04 11:27 ` Michael Ellerman [this message]
2018-06-05 3:47 ` Stewart Smith
2018-06-05 8:45 ` Gautham R Shenoy
2018-06-05 12:18 ` Michael Ellerman
2018-06-05 15:19 ` Michael Ellerman
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