From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Wise Subject: Re: ib_read_lat question Date: Thu, 21 Feb 2013 12:34:39 -0600 Message-ID: <512668BF.4030908@opengridcomputing.com> References: <51265E60.1070609@opengridcomputing.com> <1828884A29C6694DAF28B7E6B8A823736F35235F@ORSMSX101.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1828884A29C6694DAF28B7E6B8A823736F35235F-P5GAC/sN6hmkrb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Hefty, Sean" Cc: "idos-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Troy Leedberg List-Id: linux-rdma@vger.kernel.org On 2/21/2013 12:27 PM, Hefty, Sean wrote: >> ib_read_lat displays RTT latency, while the other lat programs display >> RTT/2. Is this intended? Or is read_lat.c/print_report() missing a >> divide-by-two? > The tests should measure how long it takes the data to reach the destination. For writes/sends, that would be RTT/2. For reads, the destination is local, so you should want RTT. Guess that makes sense. -- 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