Date: Wed, 24 Sep 2008 21:05:40 -0700 From: Julian Elischer <julian@elischer.org> To: gnn@freebsd.org Cc: net@freebsd.org Subject: Re: Proposed patch, convert IFQ_MAXLEN to kernel tunable... Message-ID: <48DB0E14.6030607@elischer.org> In-Reply-To: <m2k5d15hke.wl%gnn@neville-neil.com> References: <m2skrq7jb1.wl%gnn@neville-neil.com> <20080924195331.GQ783@funkthat.com> <m2k5d15hke.wl%gnn@neville-neil.com>
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gnn@freebsd.org wrote: > At Wed, 24 Sep 2008 12:53:31 -0700, > John-Mark Gurney wrote: >> George V. Neville-Neil wrote this message on Tue, Sep 23, 2008 at 15:29 -0400: >>> It turns out that the last time anyone looked at this constant was >>> before 1994 and it's very likely time to turn it into a kernel >>> tunable. On hosts that have a high rate of packet transmission >>> packets can be dropped at the interface queue because this value is >>> too small. Rather than make a sweeping code change I propose the >>> following change to the macro and updating a couple of places in the >>> IP and IPv6 stacks that were using this macro to set their own global >>> variables. >> The better solution is to resurrect rwatson's patch that eliminates the >> interface queue, and does direct dispatch to the ethernet driver.. >> Usually the driver has a queue of 512 or more packets already, so putting >> them into a second queue doesn't provide much benefit besides increasing >> the amount of locking necessary to deliver packets... > > Actually I am making this change because I found on 10G hardware the > queue is too small. Also, there are many systems where you might want > to up this, usually ones that are highly biased towards transmit only, > like a multicast repeater of some sort. > One system I have seen, that I thought made sense used to define queue length globally in msecs and each interface interpretted that to a different length. > Best, > George > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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