Date: Mon, 12 Nov 2012 10:48:00 -0800 From: Alfred Perlstein <bright@mu.org> To: Andre Oppermann <oppermann@networx.ch> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Adrian Chadd <adrian@freebsd.org>, Peter Wemm <peter@wemm.org> Subject: Re: auto tuning tcp Message-ID: <50A14460.9020504@mu.org> In-Reply-To: <50A13961.1030909@networx.ch> References: <50A0A0EF.3020109@mu.org> <50A0A502.1030306@networx.ch> <50A0B8DA.9090409@mu.org> <50A0C0F4.8010706@networx.ch> <EB2C22B5-C18D-4AC2-8694-C5C0D96C07B3@mu.org> <50A13961.1030909@networx.ch>
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On 11/12/12 10:01 AM, Andre Oppermann wrote: > On 12.11.2012 18:43, Alfred Perlstein wrote: >> >> >> On Nov 12, 2012, at 1:27 AM, Andre Oppermann <oppermann@networx.ch> >> wrote: >> >>> On 12.11.2012 09:52, Alfred Perlstein wrote: >>>> On 11/11/12 11:28 PM, Andre Oppermann wrote: >>>>> On 12.11.2012 08:10, Alfred Perlstein wrote: >>>>>> I noticed that TCBHASHSIZE does not autotune. >>>>>> >>>>>> What do you think of the following algorithm? >>>>>> >>>>>> Basically round down to next power of two based on nmbclusters / 64. >>>>> >>>>> Please wait out for a real fix of the various mbuf-whatever tuning >>>>> issue I'll propose shortly. This approach may become inapproriate. >>>>> Also the mbuf limits can be changed at runtime by sysctl. >>>>> >>>> What is the timeline you are asking for to wait? >>> >>> http://svnweb.freebsd.org/changeset/base/242910 >> >> Very cool! >> >> So instead of nmbclusters, will maxsockets work? Ideas/suggestions? > > I've already added the tunable "kern.maxmbufmem" which is in pages. > That's probably not very convenient to work with. I can change it > to a percentage of phymem/kva. Would that make you happy? > It really makes sense to have the hash table be some relation to sockets rather than buffers. If you are hashing "foo-objects" you want the hash to be some relation to the max amount of "foo-objects" you'll see, not backwards derived from the number of "bar-objects" that "foo-objects" contain, right? Because we are hashing the sockets, right? not clusters. Maybe I'm wrong? I'm open to ideas. -Alfred
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