From: Christoph Hellwig <hch@lst.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: x86@kernel.org, linux-um@lists.infradead.org,
linux-raid@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>,
David Laight <david.laight.linux@gmail.com>
Subject: Re: [PATCH 8/8] lib/raid/xor: x86: Add AVX-512 optimized xor_gen()
Date: Fri, 26 Jun 2026 07:47:31 +0200 [thread overview]
Message-ID: <20260626054731.GC9629@lst.de> (raw)
In-Reply-To: <20260626043731.319287-9-ebiggers@kernel.org>
On Thu, Jun 25, 2026 at 09:37:31PM -0700, Eric Biggers wrote:
> + if (IS_ENABLED(CONFIG_X86_64) && boot_cpu_has(X86_FEATURE_AVX512F) &&
> + !boot_cpu_has(X86_FEATURE_PREFER_YMM)) {
> + /* AVX-512 will be the best; no need to try others. */
> + /* !PREFER_YMM excludes CPUs with overly-eager downclocking. */
Can you turn this into a single block comment using full sentences?
Right now the two separate comments almost feel contradictory even
if I get what you mean. While you're at it also through in a blurb
why we dont bother with AVX-512 (number of register, no one in the right
mind would bother running high performance code on modern cpus in 32-bit
mode).
next prev parent reply other threads:[~2026-06-26 5:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-26 4:37 [PATCH 0/8] x86: Remove cpu_has_xfeatures() and add AVX-512 xor_gen() Eric Biggers
2026-06-26 4:37 ` [PATCH 1/8] x86/fpu: Check for missing AVX and AVX-512 xstate bits Eric Biggers
2026-06-26 5:00 ` sashiko-bot
2026-06-26 5:39 ` Christoph Hellwig
2026-06-26 4:37 ` [PATCH 2/8] um: " Eric Biggers
2026-06-26 7:41 ` David Laight
2026-06-26 8:21 ` Anton Ivanov
2026-06-26 10:49 ` David Laight
2026-06-26 20:55 ` Eric Biggers
2026-06-26 21:33 ` David Laight
2026-06-26 4:37 ` [PATCH 3/8] crypto: x86 - Stop using cpu_has_xfeatures() Eric Biggers
2026-06-26 4:37 ` [PATCH 4/8] lib/crypto: x86: " Eric Biggers
2026-06-26 4:53 ` sashiko-bot
2026-06-26 4:37 ` [PATCH 5/8] lib/crc: " Eric Biggers
2026-06-26 4:37 ` [PATCH 6/8] x86/fpu: Remove cpu_has_xfeatures() Eric Biggers
2026-06-26 4:37 ` [PATCH 7/8] lib/raid/xor: x86: Remove redundant X86_FEATURE_OSXSAVE check Eric Biggers
2026-06-26 4:51 ` sashiko-bot
2026-06-26 5:40 ` Christoph Hellwig
2026-06-26 4:37 ` [PATCH 8/8] lib/raid/xor: x86: Add AVX-512 optimized xor_gen() Eric Biggers
2026-06-26 5:47 ` Christoph Hellwig [this message]
2026-06-26 5:47 ` Christoph Hellwig
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