From: David Laight <David.Laight@ACULAB.COM>
To: 'Eric Biggers' <ebiggers@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Andy Lutomirski" <luto@kernel.org>,
"Chang S . Bae" <chang.seok.bae@intel.com>
Subject: RE: [PATCH 0/6] Faster AES-XTS on modern x86_64 CPUs
Date: Mon, 8 Apr 2024 07:41:44 +0000 [thread overview]
Message-ID: <e49a2868626f4f9e9169ce8b8b926a49@AcuMS.aculab.com> (raw)
In-Reply-To: <20240405191904.GA1205@quark.localdomain>
From: Eric Biggers
> Sent: 05 April 2024 20:19
...
> I did some tests on Sapphire Rapids using a system call that I customized to do
> nothing except possibly a kernel_fpu_begin / kernel_fpu_end pair.
>
> On average the bare syscall took 70 ns. The syscall with the kernel_fpu_begin /
> kernel_fpu_end pair took 160 ns if the userspace program used xmm only, 340 ns
> if it used ymm, or 360 ns if it used zmm...
>
> Note that without the kernel_fpu_begin / kernel_fpu_end pair, AES-NI
> instructions cannot be used and the alternative would be xts(ecb(aes-generic)).
> On the same CPU, encrypting a single 512-byte sector with xts(ecb(aes-generic))
> takes about 2235ns. With xts-aes-vaes-avx10_512 it takes 75 ns...
So most of the cost of a single 512-byte sector is the kernel_fpu_begin().
But it is so much slower any other way it is still faster.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2024-04-08 7:42 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-26 8:02 [PATCH 0/6] Faster AES-XTS on modern x86_64 CPUs Eric Biggers
2024-03-26 8:02 ` [PATCH 1/6] x86: add kconfig symbols for assembler VAES and VPCLMULQDQ support Eric Biggers
2024-03-26 8:10 ` Ingo Molnar
2024-03-26 8:18 ` Eric Biggers
2024-03-26 8:28 ` Ingo Molnar
2024-03-26 8:03 ` [PATCH 2/6] crypto: x86/aes-xts - add AES-XTS assembly macro for modern CPUs Eric Biggers
2024-03-26 8:03 ` [PATCH 3/6] crypto: x86/aes-xts - wire up AESNI + AVX implementation Eric Biggers
2024-03-26 8:03 ` [PATCH 4/6] crypto: x86/aes-xts - wire up VAES + AVX2 implementation Eric Biggers
2024-03-26 8:03 ` [PATCH 5/6] crypto: x86/aes-xts - wire up VAES + AVX10/256 implementation Eric Biggers
2024-03-26 8:03 ` [PATCH 6/6] crypto: x86/aes-xts - wire up VAES + AVX10/512 implementation Eric Biggers
2024-03-26 8:51 ` [PATCH 0/6] Faster AES-XTS on modern x86_64 CPUs Ard Biesheuvel
2024-03-26 16:47 ` Eric Biggers
2024-04-03 8:12 ` David Laight
2024-04-04 1:35 ` Eric Biggers
2024-04-04 7:53 ` David Laight
2024-04-05 19:19 ` Eric Biggers
2024-04-08 7:41 ` David Laight [this message]
2024-04-08 12:31 ` Eric Biggers
2024-04-05 7:58 ` Herbert Xu
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