Date: Tue, 16 Apr 2013 15:56:40 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: sbruno@freebsd.org Cc: "pyunyh@gmail.com" <pyunyh@gmail.com>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, bde <bde@freebsd.org> Subject: Re: bge(4) sysctl tuneables -- a blast from the past. Message-ID: <20130416152121.G904@besplex.bde.org> In-Reply-To: <1366065356.1350.7.camel@localhost> References: <1365781568.1418.1.camel@localhost> <20130413200512.G1165@besplex.bde.org> <1366065356.1350.7.camel@localhost>
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On Mon, 15 Apr 2013, Sean Bruno wrote: >> FreeBSD has too many knobs, but it would be nice if the bge defaults weren't >> so broken, so that they don't need overriding. > > So many knobs ... well here's more. :-) Yes, adding more knobs would subtract value. > http://people.freebsd.org/~sbruno/bge_config_update.txt > > At least this gets a man page update with references to manuals. I didn't notice before that these are tunables and not sysctls. That's much more broken. Actually tuning using them like I do with sysctls would take ~10000 reboots. Tunables are bogus for anything that isn't needed for booting. Optimizations are needed for booting. Technical bugs include: - wrong defaults are claimed for *coal_ticks. The defaults are 150, but are claimed to be 150 milliseconds. These values are dimensionless, but since ticks take 1 microsecond each, 150 gives 150 microseconds, not 150 milliseconds. - *coal_bds is claimed to be a count of packes (sic). Actually, it is a count of buffer descriptors. Small packets take 1 bd, but normal packets take 2, and jumbo packets many (?). The best tuning may be depend on the average bds/packet. - the new tunables are in the wrong namespace (hw instead of dev) - the new tunables are too global (bge instead of bge.N) There are only 2 bge tunables now, and they only have half of these bugs: - hw.bge.allow_asf is in the wrong namespace - hw.bge.allow_asf is too global - dev.bge.%d.msi seems to be correct. Both of the old tunables are needed for boot-time configuration. Bruce
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