From mboxrd@z Thu Jan 1 00:00:00 1970 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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 DB956C74A36 for ; Wed, 10 Jul 2019 19:11:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B55EA20651 for ; Wed, 10 Jul 2019 19:11:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728122AbfGJTLW (ORCPT ); Wed, 10 Jul 2019 15:11:22 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:35109 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727923AbfGJTLW (ORCPT ); Wed, 10 Jul 2019 15:11:22 -0400 Received: by mail-oi1-f196.google.com with SMTP id a127so2523995oii.2; Wed, 10 Jul 2019 12:11:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=KQsowOAJzdxitXTMpH3lblSmCoy4bvYraioAuVTlH0E=; b=ZbA5rjTt/8pELagnPJKbktXwu1A0spTpj+EWh0U6z8UhCzmzyd1w+P2O4CQn+0YcBM 8WdWmSTYTST6gEHeX8HXk3RPHJl8qh9bEltssWme22uG0cnfwYpaEmJtiq9/OPnXjAMf rAjLDGrIJ5gBSwb/4i3YnxfZCayJ910dtxp8F5g6VF9Cs3t4PMP30LMdqFrJ1nUOSdvP XSUmsqK0KFznmhthc3KFRUcZx/EFlQvVUyg6ALa7x9hx5cHUg/WcqRZ+faXn5utt+ZOl UFT8isp0CBX/YhYRJ85FsGZJ3owygGAIi8l+P2FRg4D7an8DWs0sou4JhjyNce1ghtmC emAQ== X-Gm-Message-State: APjAAAVNEBbGyNpQYNf9M/978UTcuB20//Suo3Sg4CJECuzCmxInMLUJ +jlHiMdLC5DsXw3nQ1ScEzM= X-Google-Smtp-Source: APXvYqzhi60ZA8pBUMOpA7Q5O/i+52Fm54ujejeqfbXfJdwFQBqaZlwX8Hf448W4XQP0ePWxsPbU8A== X-Received: by 2002:aca:3006:: with SMTP id w6mr4486266oiw.5.1562785881206; Wed, 10 Jul 2019 12:11:21 -0700 (PDT) Received: from ?IPv6:2600:1700:65a0:78e0:514:7862:1503:8e4d? ([2600:1700:65a0:78e0:514:7862:1503:8e4d]) by smtp.gmail.com with ESMTPSA id o26sm1001874otl.34.2019.07.10.12.11.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Jul 2019 12:11:20 -0700 (PDT) Subject: Re: [PATCH v4 00/25] InfiniBand Transport (IBTRS) and Network Block Device (IBNBD) To: Jason Gunthorpe Cc: Danil Kipnis , Jack Wang , linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, axboe@kernel.dk, Christoph Hellwig , bvanassche@acm.org, dledford@redhat.com, Roman Pen , gregkh@linuxfoundation.org References: <20190620150337.7847-1-jinpuwang@gmail.com> <20190710135519.GA4051@ziepe.ca> <20190710172505.GD4051@ziepe.ca> From: Sagi Grimberg Message-ID: <930e0bc6-8c5c-97b5-c500-0bd1706b32c1@grimberg.me> Date: Wed, 10 Jul 2019 12:11:17 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190710172505.GD4051@ziepe.ca> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org >> I still do not understand why this should give any notice-able >> performance advantage. > > Usually omitting invalidations gives a healthy bump. > > Also, RDMA WRITE is generally faster than READ at the HW level in > various ways. Yes, but this should be essentially identical to running nvme-rdma with 512KB of immediate-data (the nvme term is in-capsule data). In the upstream nvme target we have inline_data_size port attribute that is tunable for that (defaults to PAGE_SIZE).