Message-ID: <1424709235.3075.22.camel@sipsolutions.net> (sfid-20150223_173401_135454_EA963663)
Subject: Re: [RFC] mac80211: use rhashtable for station table
From: Johannes Berg <johannes@sipsolutions.net>
To: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	Thomas Graf <tgraf@suug.ch>
Date: Mon, 23 Feb 2015 17:33:55 +0100
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	 <CAHNKnsSm1GOUMONPB4oB1tJ-OeWOG1XOhw=HEY8LPXhDEHEjbg@mail.gmail.com>
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On Sat, 2015-02-14 at 05:14 +0300, Sergey Ryazanov wrote:

> A nice change! Couple of years ago I did some tests with real sets of
> MACs and jhash gives a better distribution than usage of a last octet.
> 
> BTW, why do you use full address and generic jhash? Hashing of two
> least significant words could be faster. Isn't it?

Well - not sure what you're trying to say? First you're saying jhash()
was clearly better and then you're saying I shouldn't use it? ;-)

Anyway - just using the last two bytes (or even 16-bit words) won't
cover the case where the locally administered bit is set in an otherwise
unchanged address, which is getting more common for P2P.

I also don't really see any major drawbacks to hashing it all?

johannes