From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anna Schumaker Subject: Re: [PATCH v1 02/12] xprtrdma: Raise maximum payload size to one megabyte Date: Fri, 10 Jul 2015 15:41:29 -0400 Message-ID: <55A01FE9.8000309@Netapp.com> References: <20150709203242.26247.4848.stgit@manet.1015granger.net> <20150709204159.26247.44592.stgit@manet.1015granger.net> <55A01B56.2020107@Netapp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chuck Lever Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux NFS Mailing List List-Id: linux-rdma@vger.kernel.org On 07/10/2015 03:33 PM, Chuck Lever wrote: >=20 > On Jul 10, 2015, at 3:21 PM, Anna Schumaker wrote: >=20 >> Hi Chuck, >> >> On 07/09/2015 04:41 PM, Chuck Lever wrote: >>> The point of larger rsize and wsize is to reduce the per-byte cost >>> of memory registration and deregistration. Modern HCAs can typicall= y >>> handle a megabyte or more with a single registration operation. >>> >>> Signed-off-by: Chuck Lever >>> --- >>> net/sunrpc/xprtrdma/xprt_rdma.h | 3 +-- >>> 1 file changed, 1 insertion(+), 2 deletions(-) >>> >>> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/= xprt_rdma.h >>> index f49dd8b..abee472 100644 >>> --- a/net/sunrpc/xprtrdma/xprt_rdma.h >>> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h >>> @@ -165,8 +165,7 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb) >>> * struct rpcrdma_buffer. N is the max number of outstanding reques= ts. >>> */ >>> >>> -/* temporary static scatter/gather max */ >>> -#define RPCRDMA_MAX_DATA_SEGS (64) /* max scatter/gather */ >>> +#define RPCRDMA_MAX_DATA_SEGS ((1 * 1024 * 1024) / PAGE_SIZE) >> ^^^ >> What is the significance of the 1 here? >=20 > This echoes the definition of RPCSVC_MAXPAYLOAD. >=20 > =E2=80=9C1=E2=80=9D documents =E2=80=9Cone=E2=80=9D megabyte, I assum= e. Makes sense. Thanks! >=20 >=20 >> Thanks, >> Anna >> >>> #define RPCRDMA_MAX_SEGS (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = =3D 2 */ >>> >>> struct rpcrdma_buffer; >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs= " in >>> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> >> -- >> 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 >=20 > -- > Chuck Lever >=20 >=20 >=20 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html