Date:   Mon, 20 Dec 2021 16:11:25 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Herbert Xu <herbert@gondor.apana.org.au>,
        Ard Biesheuvel <ardb@kernel.org>
Cc:     linux-crypto@vger.kernel.org, Sabrina Dubroca <sd@queasysnail.net>
Subject: Re: x86 AES crypto alignment
Message-ID: <20211220161125.78bc4d66@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
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        <20211207212907.6e91821b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
        <20211220150343.4e12a4d2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
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On Mon, 20 Dec 2021 15:03:43 -0800 Jakub Kicinski wrote:
> On Tue, 7 Dec 2021 21:29:07 -0800 Jakub Kicinski wrote:
> > On Wed, 8 Dec 2021 15:40:37 +1100 Herbert Xu wrote:  
> > > There is no such thing as an alignment requirement.  If an algorithm
> > > specifies an alignment and you pass it a request which is unaligned,
> > > the Crypto API will automatically align the data for you.
> > > 
> > > So what is the actual problem here?    
> > 
> > By align you mean copy right? I'm trying to avoid the copy.  
> 
> Hm, I'm benchmarking things now and it appears to be a regression
> introduced somewhere around 5.11 / 5.12. I don't see the memcpy 
> eating 20% of performance on 5.10. Bisection time.

83c83e658863 ("crypto: aesni - refactor scatterlist processing")

is what introduced the regression.