Date: Wed, 11 Feb 2015 13:29:58 -0800 From: Sean Bruno <sbruno@ignoranthack.me> To: Sepherosa Ziehau <sepherosa@gmail.com> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: Intel 82574L (em) Message-ID: <54DBC9D6.7020602@ignoranthack.me> In-Reply-To: <CAMOc5cwG%2BmbcArAt5xSjKYrbZeA40ETZUPgi4y51r_GYYsitQw@mail.gmail.com> References: <54CBF396.3090903@ignoranthack.me> <CAMOc5cwG%2BmbcArAt5xSjKYrbZeA40ETZUPgi4y51r_GYYsitQw@mail.gmail.com>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 02/10/15 18:49, Sepherosa Ziehau wrote: > On Sat, Jan 31, 2015 at 5:11 AM, Sean Bruno > <sbruno@ignoranthack.me> wrote: >> >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 >> >> http://www.intel.com/content/dam/doc/datasheet/82574l-gbe-controller-datasheet.pdf >> >> >> According to 7.1.11, this device does indeed have 2 queues for stuff and >> or things. So, basic RSS would be possible in something like an >> Atom box. >> >> I note that the em(4) driver intentionally disables this on >> initialization. I'm up for some science on my new shiny, soon to >> be router box. Any reason not to default to 1 queue and allow >> loader.conf to raise it to 2? > > You could actually enable 2 RX rings w/o MSI-X on 82574; you still > get the benefit of hardware calculated RSS hash at least. And as > far as I have tested, 2 RX rings work for 82574L, but 2 TX rings > don't work (gave me TX watchdog timeout). And you could also use 2 > RX rings on 82571/82572/82573 and i217/i218; 2 TX rings work on > 82571 at least (you need to setup TX context for each TX descriptor > though). > > Best Regards, sephe > > I'm interested in doing this a bit as I now have 5 em(4) interfaces on my soon to be router box. I tried modifying the driver to allow num_queues to be raised and I compiled with EM_MULTIQUEUE set, and all I got for my trouble was kernel panics. I'm not sure if the code even works. sean -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQF8BAEBCgBmBQJU28nOXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRCQUFENDYzMkU3MTIxREU4RDIwOTk3REQx MjAxRUZDQTFFNzI3RTY0AAoJEBIB78oecn5k+vMIAKaDtSR6Rr4jHnojPH0K8bbv 35khkxhHiPjynRRUxOtJXqlGu8rQ2s1L3hW8V+sKYq/sI+pjmVTMrRko6+nIdDf/ bJe20S1EQxbhm74HbO28hNnG5uBjNfEP0hwEuaZHRdenua1TtnmMSnWqOh7xT1i1 3573Bx2WulgYaEEtYmnXX5x5E8C8ks6Lr4ZQptkGPJXDBtw3v59/oc2GK/P3tixL QvNPkYbFkLn+9tD6kjy05E92BOpUG84u37rlldajxXzpRkN7xaczKMERQ2VZD4lD 8b48F4im/iElJ6fsvUSJhzqW+H/ywBOgaJEjDXJgzrz0ffaMwY8vfpp4cmDkzCE= =rlKy -----END PGP SIGNATURE-----
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