From: Linus Torvalds <torvalds@linux-foundation.org>
To: John Sanpe <sanpeqf@gmail.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
rdunlap@infradead.org, unixbhaskar@gmail.com,
mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lib/bch.c: increase bitrev single conversion length
Date: Sun, 4 Feb 2024 09:09:16 +0000 [thread overview]
Message-ID: <CAHk-=wgxkAgRPb7ZZ+w7UHhp2OuV=pc_C7D+hEYcA65ieMFt0g@mail.gmail.com> (raw)
In-Reply-To: <20240204085155.6745-1-sanpeqf@gmail.com>
On Sun, 4 Feb 2024 at 08:52, John Sanpe <sanpeqf@gmail.com> wrote:
>
> Optimized the performance of the three functions (load_ecc8 store_ecc8
> and bch_encode) using a larger calculation length.
Honestly, with any optimization, you should quote performance numbers.
Also, it's questionable how meaningful this is, considering that most
architectures dop the bit swap with a byte lookup, and the 32-bit bit
swap is just four byte lookups. For all we know, this only makes
things worse.
Finally, if you actually want to do things in bigger chunks, that
->swap_bits conditional should probably be moved out of the loops, not
just have that questionable 8->32 bit expansion.
Linus
prev parent reply other threads:[~2024-02-04 9:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-04 8:51 John Sanpe
2024-02-04 9:09 ` Linus Torvalds [this message]
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