From: Coly Li <colyli@suse.de>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Kent Overstreet <kent.overstreet@gmail.com>,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
linux-bcache@vger.kernel.org
Subject: Re: [PATCH] bcache: Optimize sysfs_hprint()
Date: Mon, 30 Oct 2023 15:38:08 +0800 [thread overview]
Message-ID: <BF96F92E-B483-4FC7-B4DB-B9D76E44D9A7@suse.de> (raw)
In-Reply-To: <9b82413f1ca0b924cc139d945777e32dd22ffe41.1698575385.git.christophe.jaillet@wanadoo.fr>
> 2023年10月29日 18:30，Christophe JAILLET <christophe.jaillet@wanadoo.fr> 写道：
>
> The size of what is in 'buf' is already computed by bch_hprint(), so skip
> these bytes when calling strcat().
>
> This easily saves a few cycles. (should it matter)
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Your change does save several cpu cycles, but hurts the readability. This is not hot code path, just let strcat to do what it was designed for.
Thanks.
Coly Li
> ---
> drivers/md/bcache/sysfs.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
> index 65b8bd975ab1..798bcbeab0bb 100644
> --- a/drivers/md/bcache/sysfs.h
> +++ b/drivers/md/bcache/sysfs.h
> @@ -78,7 +78,7 @@ do { \
> do { \
> if (attr == &sysfs_ ## file) { \
> ssize_t ret = bch_hprint(buf, val); \
> - strcat(buf, "\n"); \
> + strcat(buf + ret, "\n"); \
> return ret + 1; \
> } \
> } while (0)
> --
> 2.34.1
>
prev parent reply other threads:[~2023-10-30 7:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-29 10:30 [PATCH] bcache: Optimize sysfs_hprint() Christophe JAILLET
2023-10-30 7:38 ` Coly Li [this message]
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