Date: 31 Oct 2000 10:24:12 -0500 From: Nat Lanza <magus@cs.cmu.edu> To: Andre Oppermann <oppermann@telehouse.ch> Cc: Alfred Perlstein <bright@wintelcom.net>, Bosko Milekic <bmilekic@dsuper.net>, freebsd-net@FreeBSD.ORG Subject: Re: MP: per-CPU mbuf allocation lists Message-ID: <uoclmv5vxsz.fsf@hurlame.pdl.cs.cmu.edu> In-Reply-To: Andre Oppermann's message of "Tue, 31 Oct 2000 11:39:21 %2B0100" References: <Pine.BSF.4.21.0010301256580.30271-100000@jehovah.technokratis.com> <20001030104457.E22110@fw.wintelcom.net> <39FDD039.594CED43@telehouse.ch> <uoc7l6pyail.fsf@hurlame.pdl.cs.cmu.edu> <39FEA159.EB774F1E@telehouse.ch>
next in thread | previous in thread | raw e-mail | index | archive | help
Andre Oppermann <oppermann@telehouse.ch> writes: > No. First, you contradict yourself here and second if two Apache childs > are simultaniusly running on two CPU's they are competing at the same > time for the resource mbuf and one will starve the other and we have a > lot of contention. You misunderstand. I said "if there is only one process". I wasn't talking about the Apache case, single-threaded or multi-threaded. Also, I don't see how multiple consumers on the same CPU will starve each other. Really, I don't see why a number of consumers running on a single CPU is significantly different from a single consumer on that CPU. Basically, I think you're pointing out problems that don't exist. Maybe I'm wrong and these problems are real and significant, but it's probably best to wait until this code is implemented and working and actually test it to see if you're right about this sort of starvation. > You have multiple mbuf consumers, see above. Also I made a point about > wasting mbufs when you tune the high watermark for high loads. Well, yes. With tunable knobs like that you're always going to have the one-setting-does-not-fit-all-circumstances situation. Again, I'm not convinced that this is a huge problem, and I'd rather see the code up and running and look at how it really performs before complicating it with performance tweaks that may or may not help. --nat -- nat lanza --------------------- research programmer, parallel data lab, cmu scs magus@cs.cmu.edu -------------------------------- http://www.cs.cmu.edu/~magus/ there are no whole truths; all truths are half-truths -- alfred north whitehead To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?uoclmv5vxsz.fsf>