From: Nicholas Piggin <npiggin@gmail.com>
To: Anton Blanchard <anton@ozlabs.org>
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
svaidy@linux.vnet.ibm.com, ego@linux.vnet.ibm.com,
rjw@rjwysocki.net, daniel.lezcano@linaro.org,
linuxppc-dev@lists.ozlabs.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH 1/3] cpuidle: powernv: Don't bounce between low and very low thread priority
Date: Tue, 4 Apr 2017 09:52:07 +1000 [thread overview]
Message-ID: <20170404095207.28fc5229@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <20170403215414.16951-1-anton@ozlabs.org>
On Tue, 4 Apr 2017 07:54:12 +1000
Anton Blanchard <anton@ozlabs.org> wrote:
> From: Anton Blanchard <anton@samba.org>
>
> The core of snooze_loop() continually bounces between low and very
> low thread priority. Changing thread priorities is an expensive
> operation that can negatively impact other threads on a core.
>
> All CPUs that can run PowerNV support very low priority, so we can
> avoid the change completely.
This looks good. I have HMT_lowest() which does alt feature patching
we can use for pseries and default idle code.
next prev parent reply other threads:[~2017-04-03 23:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-03 21:54 [PATCH 1/3] cpuidle: powernv: Don't bounce between low and very low thread priority Anton Blanchard
2017-04-03 21:54 ` [PATCH 2/3] cpuidle: powernv: Don't continually set thread priority in snooze_loop() Anton Blanchard
2017-04-04 4:06 ` Vaidyanathan Srinivasan
2017-04-03 21:54 ` [PATCH 3/3] cpuidle: powernv: Avoid a branch in the core snooze_loop() loop Anton Blanchard
2017-04-03 23:54 ` Nicholas Piggin
2017-04-04 4:10 ` Vaidyanathan Srinivasan
2017-04-03 23:52 ` Nicholas Piggin [this message]
2017-04-04 4:13 ` [PATCH 1/3] cpuidle: powernv: Don't bounce between low and very low thread priority Vaidyanathan Srinivasan
2017-04-04 4:04 ` Vaidyanathan Srinivasan
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