From nobody Tue Jun 29 03:40:44 2021 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 58B4E11E4A57 for ; Tue, 29 Jun 2021 03:40:57 +0000 (UTC) (envelope-from nparhar@gmail.com) Received: from mail-ej1-f49.google.com (mail-ej1-f49.google.com [209.85.218.49]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GDVcn1mMfz3Qjq for ; Tue, 29 Jun 2021 03:40:56 +0000 (UTC) (envelope-from nparhar@gmail.com) Received: by mail-ej1-f49.google.com with SMTP id nd37so33820775ejc.3 for ; Mon, 28 Jun 2021 20:40:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/nmE3BDCyx5zKY8YyE7CDNcxBcuEVBW7sWGOD/0+zk0=; b=Gv6SYOQ5yTgzBnhdkN1kP5UFplCmlGADQm3t0gs+/EB1D2kL5rH8SSl6ubZny4lnPK g3emFvRQ/fVtEgBAmOQiI68r4qRQ/P7IRJd/MGKAPlm0fY/pnAvoajV3m9GO2JGSRNck RBsvHWLncLOlRUgyv8gbT/4Smzu5wc44QoyxlHPw+QMuNMiCVelw0qyaWCklExeM4ge8 eqVCPvdbkYTX3zVUvdFQmSx2qEBnTu81eLW6nYUuR4rRdu3+jCWzB5LHeeDPZiIyJlMY zGYjDk0JP/X/MKRmORhU8ygiuoh/gLGwKlcuGmyatwqN07iWSSOOYhc1ky6pmc1ACB6T kArw== X-Gm-Message-State: AOAM5325bKF4kmJCuk4NLT8o2PR6GdEyyyte/AjaiQnXArsi+08RvWB9 7gb1GnJmxXoDwdJY1FI0r1P20+2zvoUinAiUOTg= X-Google-Smtp-Source: ABdhPJzpiKoZbNwvS7aJw/aIcPL8hLysDz2WbSBQDV6Ou4plqAlpcKxT39L2ZD5LToiqRU7gkqUD/BbBeT1u+i4DWHg= X-Received: by 2002:a17:906:1313:: with SMTP id w19mr28117875ejb.178.1624938055436; Mon, 28 Jun 2021 20:40:55 -0700 (PDT) List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 References: In-Reply-To: From: Navdeep Parhar Date: Mon, 28 Jun 2021 20:40:44 -0700 Message-ID: Subject: Re: RFC: NFS trunking (multiple TCP connections for a mount To: Rick Macklem Cc: freebsd-net Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4GDVcn1mMfz3Qjq X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-ThisMailContainsUnwantedMimeParts: N On Mon, Jun 28, 2021 at 5:23 PM Rick Macklem wrote: > > The Linux NFS client now has a mount option "nconnect", > which specifies that multiple TCP connections be created > for an NFS mount, where RPCs are done on the connections, > in a round robin fashion. (Alternating between the two TCP > connections for the case of nconnect=2.) > > The Linux man page says: > nconnect=n > When using a connection oriented protocol such as TCP, it > may sometimes be advantageous to set up multiple > connections between the client and server. For instance, > if your clients and/or servers are equipped with multiple > network interface cards (NICs), using multiple connections > to spread the load may improve overall performance. In > such cases, the nconnect option allows the user to specify > the number of connections that should be established > between the client and server up to a limit of 16. > > I don't understand how multiple TCP connections to the same > server IP address will distribute the load across multiple network > interfaces? > I thought that lagg would have handled this? > > I could easily implement this, but I only have low end hardware > to test on, so I doubt that I will see any performance improvement. Pretty much all modern NICs are multiqueue and multiple connections will distribute load across CPUs even without any lagg. I think an nconnect like option would be quite useful for NFS over high bandwidth links as it's a lot easier to saturate the pipe using multiple connections than a single one. Regards, Navdeep