From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Wise Subject: Re: [RFC] [PATCH 1/2] libibverbs: Allow 3rd party extensions to verb routines Date: Mon, 06 Jun 2011 13:28:40 -0500 Message-ID: <4DED1C58.5050507@opengridcomputing.com> References: <1828884A29C6694DAF28B7E6B8A82373012B5B@ORSMSX101.amr.corp.intel.com> <4DED00A6.4010201@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roland Dreier Cc: "Hefty, Sean" , "linux-rdma (linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org)" List-Id: linux-rdma@vger.kernel.org On 06/06/2011 01:07 PM, Roland Dreier wrote: > On Mon, Jun 6, 2011 at 9:30 AM, Steve Wise wrote: >> Will this mechanism allow an RDMA provider driver to export a new qp-related >> operation for use internally bit the supporting provider library? IE Not >> exposes to the RDMA application, but an internal interface between the >> library and driver. I have need for this with the T4 driver. > Not sure I follow this... how specifically would this work? Why does the > userspace library need help to talk to the kernel driver? > > - R. I'm investigating ways to support a kernel mode "ring the QP doorbell" for user mode QPs. This can allow optimization and coalescing of db-credits to improve the ring rate for large amounts of qps. Currently for experimentation, I hacked this by posting a special send WR (with opcode 0xdeadbeef :) ) which ends up calling my db ring function, but I need to come up with an acceptable solution. I was thinking about maybe enhancing the modify_qp verb, but perhaps this new extension proposal is a better way? I was also pondering some sort of provider-specific ioctl. But this is really internal to the provider lib and driver. I just don't want to have to implement a full character device interface for this since the uverbs interface provides this already. Steve. -- 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