From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH 0/7] IB/hfi1: Remove write() and use ioctl() for user access Date: Wed, 27 Apr 2016 10:45:07 -0400 Message-ID: <5720D073.2070802@redhat.com> References: <20160414153727.6387.96381.stgit@scvm10.sc.intel.com> <20160414164550.GC6247@obsidianresearch.com> <20160418130909.GD11508@infradead.org> <20160418174047.GB13865@obsidianresearch.com> <20160418182411.GA4904@infradead.org> <20160419173817.GF20844@obsidianresearch.com> <1828884A29C6694DAF28B7E6B8A82373AB0439B0@ORSMSX109.amr.corp.intel.com> <5717EAC1.6020602@redhat.com> <571F6795.8020808@redhat.com> <2807E5FD2F6FDA4886F6618EAC48510E22EC6A98@CRSMSX101.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="S6V4dT9J9TRRGma0w8WFaiUdMbSBuCPT7" Return-path: In-Reply-To: <2807E5FD2F6FDA4886F6618EAC48510E22EC6A98-8k97q/ur5Z2krb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Weiny, Ira" , "Hefty, Sean" , Jason Gunthorpe , Christoph Hellwig Cc: "Dalessandro, Dennis" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --S6V4dT9J9TRRGma0w8WFaiUdMbSBuCPT7 Content-Type: multipart/mixed; boundary="ui5BB9K4lts2K2RpJhil3Ab08G7AOOphq" From: Doug Ledford To: "Weiny, Ira" , "Hefty, Sean" , Jason Gunthorpe , Christoph Hellwig Cc: "Dalessandro, Dennis" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" Message-ID: <5720D073.2070802-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Subject: Re: [PATCH 0/7] IB/hfi1: Remove write() and use ioctl() for user access References: <20160414153727.6387.96381.stgit-9QXIwq+3FY+1XWohqUldA0EOCMrvLtNR@public.gmane.org> <20160414164550.GC6247-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> <20160418130909.GD11508-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> <20160418174047.GB13865-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> <20160418182411.GA4904-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> <20160419173817.GF20844-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> <1828884A29C6694DAF28B7E6B8A82373AB0439B0-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org> <5717EAC1.6020602-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> <571F6795.8020808-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> <2807E5FD2F6FDA4886F6618EAC48510E22EC6A98-8k97q/ur5Z2krb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> In-Reply-To: <2807E5FD2F6FDA4886F6618EAC48510E22EC6A98-8k97q/ur5Z2krb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> --ui5BB9K4lts2K2RpJhil3Ab08G7AOOphq Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 4/27/2016 1:21 AM, Weiny, Ira wrote: >>=20 >> On 4/20/2016 4:46 PM, Doug Ledford wrote: >> We already have precedent for requiring an IPoIB device, and it's >> associate netdevice, in order to manage some non-IP, non-Ethernet, >> IB specific items (the recent SRIOV patches being a perfect >> example). >=20 > I'm not sure this is always going to be the case. I have heard a > number of reports of IPoIBs inability to scale and a desire to not > run it. Then don't. If you set the configuration file for the IPoIB device to not start on bootup, the module will get loaded, the device will get allocated, and then it will not transmit on the wire or join any multicast groups. It will then be a perfectly fine vessel for accessing configuration, eeproms, etc. and it won't impact the fabric in any way. If, at a later point in time, you wish to actually use it, then we can look at making it better for scale. > Isn't there a way we can create a netdevice that does not have the > associated overhead of IPoIB? Yes, load IPoIB with the device turned off. Zero overhead. At the point at which you have a new IP emulation device that can be hooked into the netstack, you can use it as the ndo entry point device instead. It makes no difference in the long run, the user space tools are the same and the training for admins is the same, only the layer used to create the user visible net device changes. I snipped the rest of your email, it all centers around the incorrect assumption that IPoIB devices must be up and running in order for the configuration entry points to be used by user space tools. --ui5BB9K4lts2K2RpJhil3Ab08G7AOOphq-- --S6V4dT9J9TRRGma0w8WFaiUdMbSBuCPT7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJXINB5AAoJELgmozMOVy/dCuUP+weYhHKWVB/jezDbOrwxfoc0 VJY85SAuhrulqhAVzHkQN8b+OeWwsUVSbh0RuZIc617ZZz4qMgsHvevgqYZiGDLf hIIGwt46/nyG/pSU9pvknzk3RnbUzbuW+Anw4+47EByWYL+Uq1p0bikpbyfU8syc 98jqwU7BVBbb+UG6Tg8bkW3kCxHDtnLi5q/04nBk6sr4/wHG5kdBQbL16ixX4eiu AnvikhNFRYGWm22/eYuSZiCBOJoRClPeHdwgZ9rGjOMlK1cxsst5GTxGOVHoYJqx m9vfb9l6p4BfyyD6aVS1DUKzw/uOK8v3hEBpwoUsRQhcKanYZX7Y9Oux16ixayVz rD/aBCX2vSVnIDio6GnwrAwZORoU2+ihVy8xitL+o7SjExbYLQHJfagD3IsgfTZY gE9k9RBmXgv/BlJCajQLdGe+4xwnS8iQzc0NrKgwQdwrg9ZhKW7kB/Bd6buEkVjr uiswtH7vacd6dDW+y8FJrRb+p0V11veWlo5kb8VXCgFoiVVGrJ9UYOqV+TPs+qCB Pp+54pikOI/9tlfZKbKUs3bOA/gptp2LBj1VvdOIeBqusa8EpHnRD9C1+pe4SJL1 wMv9QVk3ixG5iGkyaEySrkQwKfvHESQQJiWQpYx+u2OXFx0htG8sNGRREdg5lPYG JieVla8KLmujQYv0L2hr =02f6 -----END PGP SIGNATURE----- --S6V4dT9J9TRRGma0w8WFaiUdMbSBuCPT7-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html