Date: Wed, 15 Sep 2010 18:14:31 +0200 From: Gary Jennejohn <gljennjohn@googlemail.com> To: Andre Oppermann <oppermann@networx.ch> Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org Subject: Re: TCP loopback socket fusing Message-ID: <20100915181431.30677523@ernst.jennejohn.org> In-Reply-To: <20100915151632.E31898@maildrop.int.zabbadoz.net> References: <4C8E0C1E.2020707@networx.ch> <20100915151632.E31898@maildrop.int.zabbadoz.net>
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On Mon, 13 Sep 2010, Andre Oppermann wrote: > Preliminary testing (with WITNESS and INVARIANTS enabled) has shown stable > operation and a rough doubling of the throughput on loopback connections. > I've tested most socket teardown cases and it behaves fine. I'm not entirely > sure I've got all possible path's but the way it is integrated should > properly defuse the sockets in all situations. > I tried this out with the following results: a) booted the new kernel, started X, started firefox -> hard hang, had to reset the box to recover. Note that firefox uses wwwoffle as a local, caching proxy and wwwwoffle is accessed through localhost:8080 b) tried (a) again to make sure it wasn't a fluke -> same result c) booted anew but started opera instead, which does _not_ use wwwoffle as its proxy (net.inet.tcp.loopfuse=1) -> OK d) I then set net.inet.tcp.loopfuse=0 before starting firefox -> OK e) set net.inet.tcp.loopfuse=1 and ran cvsup to update my CVS tree followed by checking out the changed sources, which uses loopback to talk to cvsupd -> OK So, somewhow trying to access wwwoffle through localhost:8080 causes a hard hang of the box. Whether this has something to do with the port number or just strange behavior on the part of wwwoffle I can't say, because the hard hang makes debugging impossible. By hard hang I mean that there is no visible activity, gkrellm isn't updating, mouse and keyboard are ignored and ping from a different machine shows no reaction, so I'd say the kernel is pretty much wedged. For now I'm setting net.inet.tcp.loopfuse=0 in /etc/sysctl.conf. -- Gary Jennejohn
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