Date: Mon, 19 Jan 2004 13:32:16 +0300 (MSK) From: Maxim Konovalov <maxim@macomnet.ru> To: CHOI Junho <cjh@kr.FreeBSD.org> Cc: freebsd-performance@freebsd.org Subject: Re: mbuf tuning Message-ID: <20040119132741.O42397@news1.macomnet.ru> In-Reply-To: <20040119.192257.34695172.cjh@kr.FreeBSD.org> References: <20040119.153452.10362034.cjh@kr.FreeBSD.org> <20040119.192257.34695172.cjh@kr.FreeBSD.org>
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On Mon, 19 Jan 2004, 19:22+0900, CHOI Junho wrote: > From: Mike Silbersack <silby@silby.com> > Subject: Re: mbuf tuning > Date: Mon, 19 Jan 2004 01:12:08 -0600 (CST) > > > There are no good guidelines other than "don't set it too high." Andre > > and I have talked about some ideas on how to make mbuf usage more dynamic, > > I think that he has something in the works. But at present, once you hit > > the wall, that's it. > > > > One way to reduce mbuf cluster usage is to use sendfile where possible. > > Data sent via sendfile does not use mbuf clusters, and is more memory > > efficient. If you run 5.2 or above, it's *much* more memory efficient, > > due to change Alan Cox recently made. Apache 2 will use sendfile by > > default, so if you're running apache 1, that may be one reason for an > > upgrade. > > I am using custom version of thttpd. It allocates mmap() first(builtin > method of thttpd), and it try to use sendfile() if mmap() fails(out of > mmap memory). It really works good in normal status but the problem is > that sendfile buffer is also easy to flood. I need more sendfile > buffers but I don't know how to increase sendfile buffers either(I > think it's hidden sysctl but it was more difficult to tune than > nmbclusters). With higher traffic, thttpd sometimes stuck at "sfbufa" > status when I run top(I guess it's "sendfile buffer allocation" > status). man 2 sendfile, man 7 tuning are a good start. In 5.2 you can monitor sendfile buffers usage via kern.ipc.nsfbufs* sysctls or netstat(1). [...] -- Maxim Konovalov, maxim@macomnet.ru, maxim@FreeBSD.org
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