From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yann Droneaud Subject: Re: rdma_create_qp() and max_send_wr Date: Thu, 19 May 2011 19:13:07 +0200 Message-ID: <1305825187.2359.42.camel@deela.quest-ce.net> References: <20110421115323.48b52fb35c6f209c51bccbb9807b6df0.f623dc4952.wbe@email17.secureserver.net> <1303467645.2243.47.camel@deela.quest-ce.net> <20110519060704.GA2659@mtldesk30> <1305796637.2359.6.camel@deela.quest-ce.net> <20110519093402.GB2659@mtldesk30> <1305802216.2359.11.camel@deela.quest-ce.net> <1828884A29C6694DAF28B7E6B8A82373FE8B@ORSMSX101.amr.corp.intel.com> <1305816321.2359.15.camel@deela.quest-ce.net> <1305817426.2359.23.camel@deela.quest-ce.net> <20110519154650.GD2659@mtldesk30> <1305824364.2359.37.camel@deela.quest-ce.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1305824364.2359.37.camel-H/AUWmsJYVeqvyCYKW+Xr6xOck334EZe@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Eli Cohen Cc: "Hefty, Sean" , "cait-DpaxOq6QOWMAvxtiuMwx3w@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Roland Dreier , Jack Morgenstein List-Id: linux-rdma@vger.kernel.org Hi, Le jeudi 19 mai 2011 =C3=A0 18:59 +0200, Yann Droneaud a =C3=A9crit : > Le jeudi 19 mai 2011 =C3=A0 18:46 +0300, Eli Cohen a =C3=A9crit : > > On Thu, May 19, 2011 at 05:03:45PM +0200, Yann Droneaud wrote: > > >=20 > > > To sum up: > > >=20 > > > - ibv_qp_init_attr.max_recv_wr can be set to ibv_device_attr.max_= qp_wr, > > > 16384 in my case, > > > =20 > > > - ibv_qp_init_attr.max_send_wr *cannot* be set to > > > ibv_device_attr.max_qp_wr, but it can be set to 16351. > > >=20 > > Thanks for investigating this. We'll check and send a fix. Meanwhil= e > > you can workaround this in your code. >=20 > I understand the problem (which is probably not really a problem): >=20 > In libmlx4/src/verbs.c:mlx4_create_qp() >=20 > mlx4_calc_sq_wqe_size(&attr->cap, attr->qp_type, qp); >=20 > /* > * We need to leave 2 KB + 1 WQE of headroom in the SQ to > * allow HW to prefetch. > */ This was introduced by commit 561da8d1 Handle new FW requirement for send request prefetching http://git.kernel.org/?p=3Dlibs/infiniband/libmlx4.git;a=3Dcommit;h=3D5= 61da8d1 Regards. --=20 Yann Droneaud OPTEYA -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html