From: Borislav Petkov <bp@alien8.de>
To: Aaron Tomlin <atomlin@atomlin.com>
Cc: corbet@lwn.net, anna-maria@linutronix.de, frederic@kernel.org,
tglx@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, akpm@linux-foundation.org,
pawan.kumar.gupta@linux.intel.com, feng.tang@linux.alibaba.com,
kees@kernel.org, elver@google.com, arnd@arndb.de,
fvdl@google.com, lirongqing@baidu.com, bhelgaas@google.com,
peterz@infradead.org, brgerst@gmail.com, kai.huang@intel.com,
benjamin.berg@intel.com, andrew.cooper3@citrix.com,
oleg@redhat.com, neelx@suse.com, sean@ashe.io, mproche@gmail.com,
chjohnst@gmail.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/idle: Mark "idle=poll" as deprecated
Date: Mon, 19 Jan 2026 11:21:16 +0100 [thread overview]
Message-ID: <20260119102116.GAaW4FnNBECNPFzAW3@fat_crate.local> (raw)
In-Reply-To: <20260118231009.3194039-1-atomlin@atomlin.com>
On Sun, Jan 18, 2026 at 06:10:09PM -0500, Aaron Tomlin wrote:
> The "idle=poll" boot parameter is a blunt instrument that forces all
> CPUs in the system into a continuous "polling" state. While effective
> at eliminating wake-up latency, this global override is architecturally
> obsolete and inefficient on modern multicore systems.
Nope.
It is still very useful when you want to stop the machine from entering sleep
states.
> By writing special value "n/a" to the per-CPU sysfs node
> /sys/devices/system/cpu/cpuN/power/pm_qos_resume_latency_us, userspace
> can force a specific CPU to poll without imposing this cost globally.
You can't do that on the kernel command line and thus prevent entering sleep
states from the get-go.
So no, it ain't broke so no need to fix it.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2026-01-19 10:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-18 23:10 Aaron Tomlin
2026-01-19 10:21 ` Borislav Petkov [this message]
2026-01-19 12:41 ` Aaron Tomlin
2026-01-19 13:25 ` Borislav Petkov
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