Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 481D2C07E85 for ; Tue, 11 Dec 2018 14:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04C442084A for ; Tue, 11 Dec 2018 14:02:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qYxzC/Hr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 04C442084A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726687AbeLKOCo (ORCPT ); Tue, 11 Dec 2018 09:02:44 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:35796 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726350AbeLKOCo (ORCPT ); Tue, 11 Dec 2018 09:02:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=EQiVUkaZONlrMtZy8ywggDvRO0zym7dKxsR2zgl4hus=; b=qYxzC/HrSuosZHrEow7CxLop0 6XxnQOT3WaZwdjBNEH2yqaVbh9HYTfhySamehyUGPL+DVvwbr6cCUl11ESe3VPskvQf9vBvyOZysT EOZTCdkjTKinLB9g6WOn7U7zouosxqS4AmYSe2Mfj3y2GF4+1D07jhnOLyhKN3322xESDv7QYWPky JP2lC4868oMAJt+ySjQpSgsKh2D90TisRSBq7IHD4QxOu1IkxcSlye3Lcuh0h4r4jHUhcatpblj/W EXi1Zt6y+ByU119a3ydAuyhQXBhD3CcBO1LbO+QIgB5EA0u4wgjO/aDS+xFwJaHzsf+Jn8h232Xx4 3SYqrXO9g==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWicV-0001NO-12; Tue, 11 Dec 2018 14:02:43 +0000 Date: Tue, 11 Dec 2018 06:02:42 -0800 From: Christoph Hellwig To: Chuck Lever Cc: anna.schumaker@netapp.com, linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH v3 05/24] xprtrdma: Reduce max_frwr_depth Message-ID: <20181211140242.GC30471@infradead.org> References: <20181210161723.4198.51071.stgit@manet.1015granger.net> <20181210162945.4198.24714.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181210162945.4198.24714.stgit@manet.1015granger.net> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, Dec 10, 2018 at 11:29:45AM -0500, Chuck Lever wrote: > Some devices advertise a large max_fast_reg_page_list_len > capability, but perform optimally when MRs are significantly smaller > than that depth -- probably when the MR itself is no larger than a > page. > > By default, the RDMA R/W core API uses max_sge_rd as the maximum > page depth for MRs. For some devices, the value of max_sge_rd is > 1, which is also not optimal. Thus, when max_sge_rd is larger than > 1, use that value. Otherwise use the value of the > max_fast_reg_page_list_len attribute. > > I've tested this with a couple of devices, and it reproducibly > improves the throughput of large I/Os by several percent. Can you list which devices for reference in the changelog?