From: Shakeel Butt <shakeel.butt@linux.dev>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Dennis Zhou <dennis@kernel.org>,
Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@gentwo.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] arm64: remove HAVE_CMPXCHG_LOCAL
Date: Wed, 18 Feb 2026 14:07:57 -0800 [thread overview]
Message-ID: <aZY30X9bpsV-nPsm@linux.dev> (raw)
In-Reply-To: <20260215033944.16374-1-jszhang@kernel.org>
On Sun, Feb 15, 2026 at 11:39:44AM +0800, Jisheng Zhang wrote:
> It turns out the generic disable/enable irq this_cpu_cmpxchg
> implementation is faster than LL/SC or lse implementation. Remove
> HAVE_CMPXCHG_LOCAL for better performance on arm64.
>
> Tested on Quad 1.9GHZ CA55 platform:
> average mod_node_page_state() cost decreases from 167ns to 103ns
> the spawn (30 duration) benchmark in unixbench is improved
> from 147494 lps to 150561 lps, improved by 2.1%
>
> Tested on Quad 2.1GHZ CA73 platform:
> average mod_node_page_state() cost decreases from 113ns to 85ns
> the spawn (30 duration) benchmark in unixbench is improved
> from 209844 lps to 212581 lps, improved by 1.3%
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Please note that mod_node_page_state() can be called in NMI context and
generic disable/enable irq are not safe against NMIs (newer arm arch supports
NMI).
next prev parent reply other threads:[~2026-02-18 22:08 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-15 3:39 Jisheng Zhang
2026-02-16 10:59 ` Dev Jain
2026-02-16 11:00 ` Will Deacon
2026-02-16 15:29 ` Dev Jain
2026-02-17 13:53 ` Catalin Marinas
2026-02-17 15:00 ` Will Deacon
2026-02-17 16:48 ` Catalin Marinas
2026-02-18 4:01 ` K Prateek Nayak
2026-02-18 9:29 ` Catalin Marinas
2026-02-17 17:19 ` Christoph Lameter (Ampere)
2026-02-20 6:14 ` Jisheng Zhang
2026-02-18 22:07 ` Shakeel Butt [this message]
2026-02-20 6:20 ` Jisheng Zhang
2026-02-20 23:27 ` Shakeel Butt
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