From: Herbert Xu <herbert@gondor.apana.org.au>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Matthew Wilcox <willy@infradead.org>,
David Laight <David.Laight@aculab.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Thomas Graf <tgraf@suug.ch>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
"rcu@vger.kernel.org" <rcu@vger.kernel.org>
Subject: Re: [PATCH 0/1] Rosebush, a new hash table
Date: Sun, 25 Feb 2024 13:53:35 +0800 [thread overview]
Message-ID: <ZdrV3+kNz/ez4iai@gondor.apana.org.au> (raw)
In-Reply-To: <5p5sypt3y643rr7kp66lhmgksgtuvdgijrryh53mqiiqkrgyty@d4zcnya22owg>
On Sun, Feb 25, 2024 at 12:51:06AM -0500, Kent Overstreet wrote:
>
> but your distribution actually is accurate in general, golden ratio hash
> is relly nice for sequential integers. the actual problem with your test
> is that you're testing 100% occupancy - no one does that.
>
> 75% occupancy, siphash:
> 0: 933
> 1: 60
> 2: 6
> 3: 1
> 4: 0
>
> that looks about right to me.
The point is that the worst-case length grows with the size of
the table so it won't always be 3. You need to take into account
the largest table size that you will support.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2024-02-25 5:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 20:37 [PATCH 0/1] Rosebush, a new hash table Matthew Wilcox (Oracle)
2024-02-22 20:37 ` [PATCH 1/1] rosebush: Add new data structure Matthew Wilcox (Oracle)
2024-02-25 6:38 ` Al Viro
2024-02-23 11:37 ` [PATCH 0/1] Rosebush, a new hash table Peng Zhang
2024-02-23 13:55 ` Jason A. Donenfeld
2024-02-23 18:40 ` Kent Overstreet
2024-02-24 0:20 ` Herbert Xu
2024-02-24 22:10 ` David Laight
2024-02-25 0:50 ` Herbert Xu
2024-02-25 3:20 ` Kent Overstreet
2024-02-25 3:18 ` Kent Overstreet
2024-02-25 5:01 ` Matthew Wilcox
2024-02-25 5:32 ` Herbert Xu
2024-02-25 5:51 ` Kent Overstreet
2024-02-25 5:53 ` Herbert Xu [this message]
2024-02-25 6:14 ` Kent Overstreet
2024-02-25 6:17 ` Herbert Xu
2024-02-25 14:47 ` David Laight
2024-02-25 21:48 ` Kent Overstreet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZdrV3+kNz/ez4iai@gondor.apana.org.au \
--to=herbert@gondor.apana.org.au \
--cc=David.Laight@aculab.com \
--cc=kent.overstreet@linux.dev \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maple-tree@lists.infradead.org \
--cc=netdev@vger.kernel.org \
--cc=rcu@vger.kernel.org \
--cc=tgraf@suug.ch \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).