Date: Wed, 22 Aug 2012 22:31:29 -0600 From: Warner Losh <imp@bsdimp.com> To: Peter Jeremy <peter@rulingia.com> Cc: YongHyeon PYUN <pyunyh@gmail.com>, freebsd-current@freebsd.org Subject: Re: dhclient cause up/down cycle after 239356 ? Message-ID: <B918DF2C-2606-496C-B8F6-614E43A279EA@bsdimp.com> In-Reply-To: <20120823013534.GA31015@server.rulingia.com> References: <20120821095527.GA33206@hell.ukr.net> <20120822171253.GB3300@michelle.cdnetworks.com> <20120822172822.GA52909@hell.ukr.net> <201208221535.01598.jhb@freebsd.org> <20120823013534.GA31015@server.rulingia.com>
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On Aug 22, 2012, at 7:35 PM, Peter Jeremy wrote: > On 2012-Aug-22 15:35:01 -0400, John Baldwin <jhb@freebsd.org> wrote: >> Hmm. Perhaps we could use a debouncer to ignore "short" link flaps? = Kind of >> gross (and OpenBSD doesn't do this). For now this change basically = ignores >> link up events if they occur with 5 seconds of the link down event. = The 5 is >> hardcoded which is kind of yuck. >=20 > I'm also a bit concerned about this for similar reasons to adrian@. > We need to distinguish between short link outages caused by (eg) a > switch admin reconfiguring the switch (which needs the lease to be > re-checked) and those caused by broken NICs which report link status > changes when they are touched. Maybe an alternative is to just ignore > link flaps when they occur within a few seconds of a script_go(). > (And/or make the ignore timeout configurable). >=20 > Apart from fxp(4), does anyone know how many NICs are similarly > broken? >=20 > Does anyone know why this issue doesn't bite OpenBSD? Does it have > a work-around to avoid resetting the link, not report link status > changes or just no-one has noticed the issue? Speaking of fxp(4), can't it defer reporting link status changes during = the reset sequence it must perform? Wouldn't it be better to fix the = broken driver(s) to behave better than to add a twisty maze of hacks to = dhclient? Warner
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