From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] arm64/crypto: issue aese/aesmc instructions in pairs
Date: Tue, 17 Mar 2015 18:09:58 +0000 [thread overview]
Message-ID: <20150317180957.GC8399@arm.com> (raw)
In-Reply-To: <1426615513-28587-1-git-send-email-ard.biesheuvel@linaro.org>
On Tue, Mar 17, 2015 at 06:05:13PM +0000, Ard Biesheuvel wrote:
> This changes the AES core transform implementations to issue aese/aesmc
> (and aesd/aesimc) in pairs. This enables a micro-architectural optimization
> in recent Cortex-A5x cores that improves performance by 50-90%.
>
> Measured performance in cycles per byte (Cortex-A57):
>
> CBC enc CBC dec CTR
> before 3.64 1.34 1.32
> after 1.95 0.85 0.93
>
> Note that this results in a ~5% performance decrease for older cores.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro•org>
> ---
>
> Will,
>
> This is the optimization you yourself mentioned to me about a year ago
> (or even longer perhaps?) Anyway, we have now been able to confirm it
> on a sample 'in the wild', (i.e., a Galaxy S6 phone)
I barely remember one day to the next, but hey! I'll queue this for 4.1.
Will
prev parent reply other threads:[~2015-03-17 18:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-17 18:05 [PATCH] arm64/crypto: issue aese/aesmc instructions in pairs Ard Biesheuvel
2015-03-17 18:09 ` Will Deacon [this message]
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