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=-4.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 F00EBC41604 for ; Tue, 6 Oct 2020 19:36:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66399206F4 for ; Tue, 6 Oct 2020 19:36:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IPhVRc11" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725962AbgJFTgN (ORCPT ); Tue, 6 Oct 2020 15:36:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:52527 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbgJFTgN (ORCPT ); Tue, 6 Oct 2020 15:36:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602012972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=N/7H6cvyS654XVvdfi3xpFiwAkZtjXGpPa8qC11SASc=; b=IPhVRc11hMIm3sovsvUOypen1h67ACn/G4UjrdpDaVhxBrcZpwq24zf46D9fDpeb4ILeu1 yIdVjJJv54o4Cj3C6j4B39z5jmRuAs/j+KYzzfwtzHDz55nQvep9JWcEXqXxbZWY1MkDcL XRCvAxECv2ss5oUJ68GLIZM8/vhX9xk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-438-dy2bgqdoO7OpH9zLOHWKiA-1; Tue, 06 Oct 2020 15:36:10 -0400 X-MC-Unique: dy2bgqdoO7OpH9zLOHWKiA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8631F1019624; Tue, 6 Oct 2020 19:36:09 +0000 (UTC) Received: from [172.16.176.1] (ovpn-64-66.rdu2.redhat.com [10.10.64.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 34C822C31E; Tue, 6 Oct 2020 19:36:08 +0000 (UTC) From: "Benjamin Coddington" To: "J. Bruce Fields" Cc: linux-nfs@vger.kernel.org Subject: Re: unsharing tcp connections from different NFS mounts Date: Tue, 06 Oct 2020 15:36:07 -0400 Message-ID: <95542179-0C20-4A1F-A835-77E73AD70DB8@redhat.com> In-Reply-To: <20201006151335.GB28306@fieldses.org> References: <20201006151335.GB28306@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; format=flowed X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On 6 Oct 2020, at 11:13, J. Bruce Fields wrote: > NFSv4.1+ differs from earlier versions in that it always performs > trunking discovery that results in mounts to the same server sharing a > TCP connection. > > It turns out this results in performance regressions for some users; > apparently the workload on one mount interferes with performance of > another mount, and they were previously able to work around the > problem > by using different server IP addresses for the different mounts. > > Am I overlooking some hack that would reenable the previous behavior? > Or would people be averse to an "-o noshareconn" option? I suppose you could just toggle the nfs4_unique_id parameter. This seems to work: flock /sys/module/nfs/parameters/nfs4_unique_id bash -c "OLD_ID=\$(cat /sys/module/nfs/parameters/nfs4_unique_id); echo imalittleteapot > /sys/module/nfs/parameters/nfs4_unique_id; mount -ov4,sec=sys 10.0.1.200:/exports /mnt/fedora2; echo \$OLD_ID > /sys/module/nfs/parameters/nfs4_unique_id" I'm trying to think of a reason why this is a bad idea, and not coming up with any. Can we support users that have already found this solution? Ben