From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH] arm64: Get rid of ARM64_HAS_NO_HW_PREFETCH
Date: Thu, 23 Nov 2023 19:24:53 +0000 [thread overview]
Message-ID: <ZV-nBSCHHFh8H8lk@arm.com> (raw)
In-Reply-To: <20231122133754.1240687-1-maz@kernel.org>
On Wed, Nov 22, 2023 at 01:37:54PM +0000, Marc Zyngier wrote:
> Back in 2016, it was argued that implementations lacking a HW
> prefetcher could be helped by sprinkling a number of PRFM
> instructions in strategic locations.
>
> In 2023, the one platform that presumably needed this hack is no
> longer in active use (let alone maintained), and an quick
> experiment shows dropping this hack only leads to a 0.4% drop
> on a full kernel compilation (tested on a MT30-GS0 48 CPU system).
>
> Given that this is pretty much in the noise department and that
> it may give odd ideas to other implementers, drop the hack for
> good.
>
> Suggested-by: Will Deacon <will@kernel.org>
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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next prev parent reply other threads:[~2023-11-23 19:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 13:37 [PATCH] arm64: Get rid of ARM64_HAS_NO_HW_PREFETCH Marc Zyngier
2023-11-23 19:24 ` Catalin Marinas [this message]
2023-12-05 15:16 ` Will Deacon
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