Date: Wed, 8 Sep 1999 20:02:01 -0500 (CDT) From: Jonathan Lemon <jlemon@americantv.com> To: nordwick@scam.xcf.berkeley.edu, hackers@freebsd.org Subject: Re: message queues for I/O (usenix paper) Message-ID: <199909090102.UAA26715@free.pcs> In-Reply-To: <local.mail.freebsd-hackers/19990909003757.66140.qmail@scam.xcf.berkeley.edu>
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In article <local.mail.freebsd-hackers/19990909003757.66140.qmail@scam.xcf.berkeley.edu> you write: >There is alot of talk going on over at the linux-kernel mailing list >about implementing synchronous messaging for I/O. They are talking about >a paper that was presented at USENIX: > > http://www.cs.rice.edu/~gaurav/papers/usenix99.ps > >The general idea is that select() and poll() fall over with large numbers of >file descriptors for two reasons. First, scanning the interest list begins to >consume more time. Second, the stateless nature between calls means that >alot of redundant processing occurs. The solution these guys (the authors) >say is to have a way of registering interest in descriptors, then you can >call a procedure to find out what has changed since last time. > >I personally think that select() is just fine and can be implemented >more efficiently than currently, but I would be willing to give it a shot >at both cooperating with the Linux people to get a good Linux/FreeBSD >API layed down and then implementing it. > >I know some of you heard this paper presented so does anybody have any >ideas about it? Yes. I don't particularly like some of the things in the paper, although it does have several good concepts. I have an implementation that does exactly this, and have a line on two other implementations that do the same thing (but in a different fashion). Unfortunately, all of these are somewhat problem-specific and are not a general solution. I've spent some time working on a generic implementation that draws its ideas from several places. I hope to be in a position where I can work on this almost full time within a month. -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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