From: Peter Zijlstra <peterz@infradead.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
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Valentin Schneider <vschneid@redhat.com>,
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Li Chen <chenl311@chinatelecom.cn>,
Bibo Mao <maobibo@loongson.cn>, Mete Durlu <meted@linux.ibm.com>,
Tobias Huschle <huschle@linux.ibm.com>,
Easwar Hariharan <easwar.hariharan@linux.microsoft.com>,
Guo Weikang <guoweikang.kernel@gmail.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Brian Gerst <brgerst@gmail.com>,
Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>,
Swapnil Sapkal <swapnil.sapkal@amd.com>,
"Yury Norov [NVIDIA]" <yury.norov@gmail.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Andrea Righi <arighi@nvidia.com>,
Yicong Yang <yangyicong@hisilicon.com>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vinicius Costa Gomes <vinicius.gomes@intel.com>
Subject: Re: [PATCH v7 4/8] powerpc/smp: Introduce CONFIG_SCHED_MC to guard MC scheduling bits
Date: Tue, 14 Oct 2025 16:17:30 +0200 [thread overview]
Message-ID: <20251014141730.GZ3245006@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMuHMdUD8RZqPL5ZYyJrwJB+XL_Tkn-rsLx7WvUmn6y5M_tAtw@mail.gmail.com>
On Tue, Oct 14, 2025 at 02:37:11PM +0200, Geert Uytterhoeven wrote:
> > > > + help
> > > > + Improves the CPU scheduler's decision making when dealing with
> > > > + MultiThreading at a cost of slightly increased overhead in some
> > > > + places. If unsure say N here.
> > >
> > > So it should default to n?
> >
> > That's just help text that got carried around. Many of the architectures
> > that had default y still had this text on. I suppose we can change it if
> > someone cares.
>
> Please do so.
How about we remove the recommendation like so? There are many help
things that do not have a recommendation. Mostly these options add a
little code and the most expensive bits tend to be gated by
static_branch() so it really shouldn't be that bit of a burden.
CONFIG_SMP was the big one for the scheduler, and Ingo recently removed
that (he did an effective unifdef CONFIG_SMP=y on the scheduler code).
---
diff --git a/arch/Kconfig b/arch/Kconfig
index ebe08b9186ad..3d8e2025a4ac 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -57,7 +57,7 @@ config SCHED_SMT
help
Improves the CPU scheduler's decision making when dealing with
MultiThreading at a cost of slightly increased overhead in some
- places. If unsure say N here.
+ places.
config SCHED_CLUSTER
bool "Cluster scheduler support"
@@ -77,7 +77,7 @@ config SCHED_MC
help
Multi-core scheduler support improves the CPU scheduler's decision
making when dealing with multi-core CPU chips at a cost of slightly
- increased overhead in some places. If unsure say N here.
+ increased overhead in some places.
# Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
config HOTPLUG_CORE_SYNC
next prev parent reply other threads:[~2025-10-14 14:18 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-26 4:13 [PATCH v7 0/8] sched/fair: Get rid of sched_domains_curr_level hack for tl->cpumask() K Prateek Nayak
2025-08-26 4:13 ` [PATCH v7 1/8] " K Prateek Nayak
2025-08-28 23:06 ` Tim Chen
2025-08-26 4:13 ` [PATCH v7 2/8] powerpc/smp: Rename cpu_corgroup_* to cpu_corgrp_* K Prateek Nayak
2025-08-26 5:02 ` Christophe Leroy
2025-09-01 3:05 ` K Prateek Nayak
2025-08-26 4:13 ` [PATCH v7 3/8] powerpc/smp: Export cpu_coregroup_mask() K Prateek Nayak
2025-08-26 4:54 ` Christophe Leroy
2025-08-26 4:13 ` [PATCH v7 4/8] powerpc/smp: Introduce CONFIG_SCHED_MC to guard MC scheduling bits K Prateek Nayak
2025-08-26 4:49 ` Christophe Leroy
2025-08-26 8:07 ` Peter Zijlstra
2025-08-26 9:43 ` Peter Zijlstra
2025-08-26 9:59 ` Peter Zijlstra
2025-08-28 14:43 ` Shrikanth Hegde
2025-09-01 8:35 ` Peter Zijlstra
2025-09-01 8:52 ` Peter Zijlstra
2025-10-14 9:25 ` Geert Uytterhoeven
2025-10-14 9:42 ` Peter Zijlstra
2025-10-14 12:37 ` Geert Uytterhoeven
2025-10-14 14:17 ` Peter Zijlstra [this message]
2025-10-14 15:04 ` Geert Uytterhoeven
2025-08-26 9:27 ` Shrikanth Hegde
2025-09-01 4:50 ` K Prateek Nayak
2025-08-26 4:13 ` [PATCH v7 5/8] sched/topology: Unify tl_smt_mask() across core and all arch K Prateek Nayak
2025-08-26 5:13 ` Christophe Leroy
2025-08-26 8:01 ` Peter Zijlstra
2025-08-26 8:11 ` Christophe Leroy
2025-08-26 8:24 ` Peter Zijlstra
2025-08-26 4:13 ` [PATCH v7 6/8] sched/topology: Unify tl_cls_mask() across core and x86 K Prateek Nayak
2025-08-26 5:14 ` Christophe Leroy
2025-08-26 4:13 ` [PATCH v7 7/8] sched/topology: Unify tl_mc_mask() across core and all arch K Prateek Nayak
2025-08-26 5:15 ` Christophe Leroy
2025-08-26 4:13 ` [PATCH v7 8/8] sched/topology: Unify tl_pkg_mask() " K Prateek Nayak
2025-08-26 5:16 ` Christophe Leroy
2025-08-26 10:05 ` [PATCH v7 0/8] sched/fair: Get rid of sched_domains_curr_level hack for tl->cpumask() Shrikanth Hegde
2025-08-26 10:13 ` Peter Zijlstra
2025-08-29 7:53 ` Valentin Schneider
2025-08-29 8:53 ` Shrikanth Hegde
2025-09-01 4:39 ` K Prateek Nayak
2025-09-01 8:58 ` Peter Zijlstra
2025-09-01 17:06 ` Shrikanth Hegde
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