From owner-freebsd-current@FreeBSD.ORG Fri Sep 29 21:59:35 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D371116A412 for ; Fri, 29 Sep 2006 21:59:35 +0000 (UTC) (envelope-from andre@freebsd.org) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id B6C0C43D88 for ; Fri, 29 Sep 2006 21:59:25 +0000 (GMT) (envelope-from andre@freebsd.org) Received: (qmail 97872 invoked from network); 29 Sep 2006 22:00:36 -0000 Received: from dotat.atdotat.at (HELO [62.48.0.47]) ([62.48.0.47]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 29 Sep 2006 22:00:36 -0000 Message-ID: <451D973C.8070004@freebsd.org> Date: Fri, 29 Sep 2006 23:59:24 +0200 From: Andre Oppermann User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8b) Gecko/20050217 MIME-Version: 1.0 To: John-Mark Gurney References: <451C4850.5030302@freebsd.org> <451D884F.1030807@cisco.com> <20060929213722.GR80527@funkthat.com> In-Reply-To: <20060929213722.GR80527@funkthat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, Randall Stewart , freebsd-current@freebsd.org, Mike Silbersack , gallatin@cs.duke.edu Subject: Re: Much improved sosend_*() functions X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Sep 2006 21:59:35 -0000 John-Mark Gurney wrote: > Randall Stewart wrote this message on Fri, Sep 29, 2006 at 16:55 -0400: > >>Mike Silbersack wrote: >> >>>On Fri, 29 Sep 2006, Andre Oppermann wrote: >>> >>> >>> >>>>over it an copies the data into the mbufs by using uiomove(). >>>>sosend_dgram() >>>>and sosend_generic() are change to use m_uiotombuf() instead of >>>>sosend_copyin(). >>> >>> >>>Can you do some UDP testing with 512b, 1K, 2K, 4K, 8K, and 16K packets to >>>see if performance changes there as well? >> >>Hmm.. I would think 512b and 1K will not show any >>improvement.. since they would probably end up either >>in an mbuf chain.. or a single 2k (or maybe 4k) cluster.. >>... quite a waste.. now if we had 512b and 1k clusters that >>would be cool... >> >>In fact I have always thought we should: >> >>a) have no data portion in an mbuf.. just pointers i.e. always >> an EXT >> >>b) Have a 256/512 and 1k cluster too.. >> >>This would allow copy by reference no matter what size si >>being sent... > > > IMO it's quite a waste of memory the way we have thigns now, though > w/ TSO it'll change things... Receive path != send path. > w/ 512 byte mbuf and a 2k cluster just to store just 1514 bytes of data, > that's only 60% effeciency wrt to memory usage... so, we currently > waste 40% of memory allocated to mbufs+clusters... Even reducing > mbufs back to 128 or 256 would be a big help, though IPSEC I believe > would have issues... mbufs are 256 bytes. > Hmmm.. If we switched clusters to 1536 bytes in size, we'd be able to > fit 8 in 12k (though I guess for 8k page boxes we'd do 16 in 24k)... The > only issue w/ that would be that a few of the clusters would possibly > split page boundaries... How much this would effect performance would > be an interesting question to answer... Splitting page boundaries is not an option as it may not be physically contigous. Just don't overengineer the stuff. Mbufs are only used temporarily and a bit theoretical waste is not much a problem (so far at least). -- Andre