Date: Mon, 24 Apr 2006 03:19:25 -0700 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Chuck Swiger" <cswiger@mac.com> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: RE: anyone understand torvald's critique of freebsd? Message-ID: <LOBBIFDAGNMAMLGJJCKNIEMMFDAA.tedm@toybox.placo.com> In-Reply-To: <444AEB7E.1030406@mac.com>
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>-----Original Message----- >From: Chuck Swiger [mailto:cswiger@mac.com] >Sent: Saturday, April 22, 2006 7:51 PM >To: Ted Mittelstaedt >Cc: freebsd-questions >Subject: Re: anyone understand torvald's critique of freebsd? > > >Ted Mittelstaedt wrote: >> Then why does Linus think manipulating the VM page table mappings >> is bad? That is, why does he -really- think it's bad, not the >> publically-given reason? Is it because Linux is extrordinairly >> inefficient in page table mappings due to some structural decision >> that Linus made that cannot be reversed now, that it could never >> be any good at it? Or is there some other reason? > >I can't speak with certainty as to what someone else might >think; no doubt Linus >is entirely capable of explaining his own position should you >wish to inquire, The guy is bitching about an option that's not even turned on, thus it's not a legitimate criticism - there's an ulterior motive somewhere. He isn't going to explain this of course - if he was being honest he never would have bitched about it in the first place. >however.... :-) > >I think Linus doesn't care much for Zero-copy sockets because >for the common >case of 1500/1504-byte MTU, you end up wasting at least 60% of >a 4096-byte page >for each packet, and maybe ?three? times that much if your >hardware splits the >packet into separate pages for the mbuf header, the packet >headers, and the >packet data. > ram is cheap these days. I've seen things before that are a lot faster to do the memory-hogging way. If this is one of these then the ram usage shouldn't be an issue. Ted
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