From: Martin Wilck <martin.wilck@suse.com>
To: "ming.lei@redhat.com" <ming.lei@redhat.com>,
"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH V2] lib/sbitmap: kill 'depth' from sbitmap_word
Date: Tue, 8 Feb 2022 07:46:03 +0000 [thread overview]
Message-ID: <0f28be75075d260651b215fa435a40152feef93f.camel@suse.com> (raw)
In-Reply-To: <20220110072945.347535-1-ming.lei@redhat.com>
On Mon, 2022-01-10 at 15:29 +0800, Ming Lei wrote:
> Only the last sbitmap_word can have different depth, and all the
> others
> must have same depth of 1U << sb->shift, so not necessary to store it
> in
> sbitmap_word, and it can be retrieved easily and efficiently by
> adding
> one internal helper of __map_depth(sb, index).
>
> Remove 'depth' field from sbitmap_word, then the annotation of
> ____cacheline_aligned_in_smp for 'word' isn't needed any more.
>
> Not see performance effect when running high parallel IOPS test on
> null_blk.
>
> This way saves us one cacheline(usually 64 words) per each
> sbitmap_word.
>
> Cc: Martin Wilck <martin.wilck@suse.com>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
next prev parent reply other threads:[~2022-02-08 7:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-10 7:29 [PATCH V2] lib/sbitmap: kill 'depth' from sbitmap_word Ming Lei
2022-02-08 3:23 ` Ming Lei
2022-02-08 7:46 ` Martin Wilck [this message]
2022-02-08 9:02 ` John Garry
2022-02-08 13:54 ` Jens Axboe
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