From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [RFC] zero-copy extensions for rsockets Date: Tue, 31 Jul 2012 15:34:50 -0600 Message-ID: <20120731213450.GA5787@obsidianresearch.com> References: <1828884A29C6694DAF28B7E6B8A8237346A6E8D5@ORSMSX101.amr.corp.intel.com> <20120731183243.GA4755@obsidianresearch.com> <1828884A29C6694DAF28B7E6B8A8237346A6E926@ORSMSX101.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1828884A29C6694DAF28B7E6B8A8237346A6E926-P5GAC/sN6hmkrb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Hefty, Sean" Cc: "linux-rdma (linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org)" , "Christoph Lameter (christoph-zt5rKe7wo/JBDgjK7y7TUQ@public.gmane.org)" , "Greg KH (gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org)" List-Id: linux-rdma@vger.kernel.org On Tue, Jul 31, 2012 at 08:33:49PM +0000, Hefty, Sean wrote: > > This looks very similar to the libaio interface.. > > I did look at aio. It may be possible to use aio context in place > of ioq, and I'm open to that. I was actually modeling ioq more > after epoll than aio. It just seemed simpler to treat an ioq as a > standard fd. libaio is designed to be used along with an eventfd that provides the epoll like semantics you are talking about. Each time you call io_submit you can call io_set_eventfd() on the iocb and the aio engine will trigger that eventfd when the IO completes. poll or epoll on the eventfd fd. > My concern is that supporting a more flexible API, like aoi, would > effectively result in losing some desirable feature handling > completions, such as kernel bypass or reducing interrupts. With > aio, I'm unsure about the impact of supporting callback > notifications and the selection of each aio context on a per request > basis. I'm not sure what you are refering to here? Are you mixing up POSIX aio with libaio? They are totally different. libaio has no callback notification mechanism, just io_getevents. Jason -- 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