From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Valentin Schneider <valentin.schneider@arm.com>,
linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
qperret@google.com, Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
morten.rasmussen@arm.com, Will Deacon <will@kernel.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 2/2] arm64: defconfig: enable CONFIG_SCHED_SMT
Date: Thu, 27 Feb 2020 16:28:03 +0000 [thread overview]
Message-ID: <7f647316-00a7-69cb-5d40-733ab8c6796d@arm.com> (raw)
In-Reply-To: <20200226164118.6405-3-valentin.schneider@arm.com>
On 26.02.20 16:41, Valentin Schneider wrote:
> The (CFS) scheduler has some extra logic catering to systems with SMT, but
> that logic won't be compiled in unless the above config is set.
>
> Note that the SMT-centric codepaths are gated by the sched_smt_present
> static key, and the SMT sched_domains will only survive if the platform has
> SMT. As such, the only impact on !SMT platforms should be a slightly
> bigger kernel - no behavioural change.
>
> Distro kernels already enable it, which makes sense since there already are
> things like ThunderX2 out in the wild. Enable it for the defconfig.
[...]
>
> As for the sched_domains, this is on a hikey960:
>
> before:
> $ cat /proc/sys/kernel/sched_domain/cpu*/domain*/name | sort | uniq
> DIE
> MC
>
> after:
> $ cat /proc/sys/kernel/sched_domain/cpu*/domain*/name | sort | uniq
> DIE
> MC
Have you tested that EAS still comes up ?
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next prev parent reply other threads:[~2020-02-27 16:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 16:41 [PATCH 0/2] sched, arm64: enable CONFIG_SCHED_SMT for arm64 Valentin Schneider
2020-02-26 16:41 ` [PATCH 1/2] sched/topology: Don't enable EAS on SMT systems Valentin Schneider
2020-02-27 13:00 ` Quentin Perret
2020-02-27 16:28 ` Dietmar Eggemann
2020-02-27 16:42 ` Valentin Schneider
2020-02-26 16:41 ` [PATCH 2/2] arm64: defconfig: enable CONFIG_SCHED_SMT Valentin Schneider
2020-02-27 16:28 ` Dietmar Eggemann [this message]
2020-02-27 16:37 ` Valentin Schneider
2020-02-27 16:32 ` [PATCH 0/2] sched, arm64: enable CONFIG_SCHED_SMT for arm64 Dietmar Eggemann
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