Date: Sun, 21 Jan 2007 23:25:40 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Max Laier <max@love2party.net> Cc: freebsd-net@freebsd.org Subject: Re: slow writes on nfs with bge devices Message-ID: <20070121215054.C24780@delplex.bde.org> In-Reply-To: <200701210809.27770.max@love2party.net> References: <20070121155510.C23922@delplex.bde.org> <200701210809.27770.max@love2party.net>
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On Sun, 21 Jan 2007, Max Laier wrote: > On Sunday 21 January 2007 07:25, Bruce Evans wrote: >> nfs writes much less well with bge NICs than with other NICs (sk, fxp, > > Do you use hardware checksumming on the bge? There is an XXX in > bge_start_locked() that looks a bit suspicious to me. I use the default for that. Wouldn't checksum problems show up as errors somwhere? >>> [excessive quoting deleted] tcpdump shows a lot of intervals between nfs write requests of almost exactly 10 mS (even with HZ = 1000, but more obvious with HZ = 100) for the broken case, so the problem is apparently related to timeouts, or timeouts are masking a larger problem. (The average interval between write requests needs to be about 683 uS to avoid wasting any bandwith. fxp <-> fxp on the same network averages 708 uS. fxp <-> bge 5701 averages 3981.) Bruce
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