From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: Re: ibv_post_send/recv kernel path optimizations (was: uverbs: handle large number of entries) Date: Thu, 25 Nov 2010 17:00:50 +0200 Message-ID: <4CEE7A22.2040706@voltaire.com> References: <20101007161649.GD21206@obsidianresearch.com> <20101007165947.GD11681@bicker> <20101009231607.GA24649@obsidianresearch.com> <20101012113117.GB6742@bicker> <20101012210118.GR24268@obsidianresearch.com> <20101013091312.GB6060@bicker> <20101123071025.GI1522@bicker> <20101124221845.GH2369@obsidianresearch.com> <20101125041337.GA11049@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101125041337.GA11049-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Walukiewicz, Miroslaw" Cc: Jason Gunthorpe , Roland Dreier , Roland Dreier , Sean Hefty , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org Jason Gunthorpe wrote: > Hmm, considering your list is everything but Mellanox, maybe it makes much more sense to push the copy_to_user down into the driver - ie a ibv_poll_cq_user - then the driver can construct each CQ entry on the stack and copy it to userspace, avoid the double copy, allocation and avoid any fixed overhead of ibv_poll_cq. > > A bigger change to be sure, but remember this old thread: > http://www.mail-archive.com/linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org/msg05114.html > 2x improvement by removing allocs on the post path.. Hi Mirek, Any updates on your findings with the patches? Or. -- 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