Date: Wed, 4 Sep 2002 23:11:08 +0100 From: Dominic Marks <dominic_marks@btinternet.com> To: Dmitry Morozovsky <marck@rinet.ru> Cc: Mike Hoskins <mike@adept.org>, Charles Sprickman <spork@inch.com>, stable@FreeBSD.ORG Subject: Re: interpreting netstat -m output Message-ID: <20020904221108.GA1879@gallium> In-Reply-To: <20020905014934.J56943-100000@woozle.rinet.ru> References: <20020904212032.GA1688@gallium> <20020905014934.J56943-100000@woozle.rinet.ru>
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On Thu, Sep 05, 2002 at 02:04:05AM +0400, Dmitry Morozovsky wrote: > On Wed, 4 Sep 2002, Dominic Marks wrote: > > DM> An mbuf is a fixed length structure which contains network data. > DM> > DM> An mbuf cluster is associated with an area of memory which is used for > DM> storing more data than you can fit in a single mbuf. > DM> > DM> According the D&I 4.4 an mbuf is 128 bytes and (not all of this is > DM> available for data storage), an mbuf cluster varies in size, but > DM> defaults to 1024 bytes (but according to the book this may be different > DM> depending on CPU architecture). > > AFAIK according to /usr/src/sys/*/param.h, mbuf size if 256 (at least for > i386, see /usr/src/sys/i386/include/param.h, and is not defined for > Alphas); > > and mbcluster size defaults to 2k (I suppose the smallest 2^x to > cover standard Ethernet frame) > > however, in /usr/src/sys/i386/boot/dosboot/param.h, MCLBYTES defined as > 2^12 (4k). Don't know whether this value is really used. I would not be surprised to find that these are the current values. I quoted directly from the book which is a bit old. > Sincerely, > D.Marck [DM5020, DM268-RIPE, DM3-RIPN] > ------------------------------------------------------------------------ > *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** > ------------------------------------------------------------------------ > -- Dominic Marks Computer & Politics Geek [work]::[npl.co.uk] << dominic.marks at npl.co.uk >> [educ]::[umist.ac.uk] << notyet-known at umist.ac.uk >> [home]::[btinternet] << dominic_marks at btinternet.com >> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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