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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Arvind Sankar' <nivedita@alum.mit.edu>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 6/6] crypto: lib/sha - Combine round constants and
 message schedule
Thread-Topic: [PATCH v2 6/6] crypto: lib/sha - Combine round constants and
 message schedule
Thread-Index: AQHWpyE0sF/IXICPKESRSNEpjVVK3amhAtQw
Date:   Tue, 20 Oct 2020 21:36:00 +0000
Message-ID: <d8c1750ffcef4236904919321b872cd2@AcuMS.aculab.com>
References: <20201020203957.3512851-1-nivedita@alum.mit.edu>
 <20201020203957.3512851-7-nivedita@alum.mit.edu>
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From: Arvind Sankar
> Sent: 20 October 2020 21:40
> 
> Putting the round constants and the message schedule arrays together in
> one structure saves one register, which can be a significant benefit on
> register-constrained architectures. On x86-32 (tested on Broadwell
> Xeon), this gives a 10% performance benefit.

I'm actually stunned it makes that much difference.
The object code must be truly horrid (before and after).

There are probably other strange tweaks that give a similar
improvement.

	David

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