From owner-freebsd-net@freebsd.org Fri May 27 07:29:55 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D8173B4BD35 for ; Fri, 27 May 2016 07:29:55 +0000 (UTC) (envelope-from nparhar@gmail.com) Received: from mail-pa0-x230.google.com (mail-pa0-x230.google.com [IPv6:2607:f8b0:400e:c03::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A88FC1056; Fri, 27 May 2016 07:29:55 +0000 (UTC) (envelope-from nparhar@gmail.com) Received: by mail-pa0-x230.google.com with SMTP id eu11so28522297pad.3; Fri, 27 May 2016 00:29:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to:user-agent; bh=s3z8xufxkkFz+gEd6kq2Z6UsE2Lh/Zhz6p0BcQW8xqA=; b=M/yAOgR3rolLgUuj46knzSgT5GMrswh4sbPo0GK8d0mQiwF2FX5S0SODwLrcXo7//H BOBQHunxA1PULYP64mEqGTjNm6JB8sR6+KBF4OxRE5Qw9Wg+DrcTak5DpoFtdbKjFbYQ IDpi3HJmN1M/9u/HdvxTSKpw8If04hgS0uoF2hJR97sOmjnIh3zsGPbVMr4QhFYPlcjS 2lj9BtvttNlxLF3TWyDJ2QOhWpPWS8QgW558YFcEOFtu6DR5Hd+rUK+/LuA5TlPjqsro Thir+xvYIKCkvlXxK922ooj2pg4+dET68gKAsiGJZDADQwmMt9qaXwRZNhbLf0N3LK7J Da2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to:user-agent; bh=s3z8xufxkkFz+gEd6kq2Z6UsE2Lh/Zhz6p0BcQW8xqA=; b=G0Tto6caF3t1vQDDJFDl4lUQJQyWd0uZOHm6RlCmd9MS9ekAJL9zeXkSDqIjOG5zuK BnR1lqZkclTb8FwpomrDKI6AfC1NM+yCl2BE/V+I/6ZlDqrMI4bSFmDLka+U9I6O0QD5 r8i9epKY3r/NRglomVaNCznDYXDFpVrV7rbTaoiGnpSPp1jYSMsAX/M/ERi936ZIIdtq qa238FOoZW9QLxVD3ADmmD/QJELrOPRglrL45izo2BoVLHo96WUKB1kr2PNCj+0gXfEp 1C8y3xMMvPaGd0fueuZuV8pvH5bnT3k37JlFD5OOuOpVurlMNl4lVjanDdKxYTHSv8NU tfxQ== X-Gm-Message-State: ALyK8tJTAKhHlEcqA8yL+jb9vrhM06KJISANd0nloIMLV3RvOS/EAoGQNPKW0/IMnRBkRg== X-Received: by 10.66.136.41 with SMTP id px9mr20270211pab.80.1464334195129; Fri, 27 May 2016 00:29:55 -0700 (PDT) Received: from ox ([2601:641:c180:c600:29bb:647c:963d:7705]) by smtp.gmail.com with ESMTPSA id h16sm11119112pfj.0.2016.05.27.00.29.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 May 2016 00:29:53 -0700 (PDT) Date: Fri, 27 May 2016 00:29:51 -0700 From: Navdeep Parhar To: "K. Macy" Cc: Garrett Wollman , "dmarquess@gmail.com" , "freebsd-net@freebsd.org" Subject: Re: Changing MTU on cxgbe Message-ID: <20160527072951.GC10148@ox> Mail-Followup-To: "K. Macy" , Garrett Wollman , "dmarquess@gmail.com" , "freebsd-net@freebsd.org" References: <201605270457.u4R4vYqu018911@hergotha.csail.mit.edu> <20160527063731.GB10148@ox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 May 2016 07:29:55 -0000 On Fri, May 27, 2016 at 12:23:02AM -0700, K. Macy wrote: > On Thursday, May 26, 2016, Navdeep Parhar wrote: > > > On Fri, May 27, 2016 at 12:57:34AM -0400, Garrett Wollman wrote: > > > In article < > > CAJpsHY4vF5Ky6GuAusLOOROgiQuyD2CcRmVxu8x3cArQRZxcbg@mail.gmail.com > > > you write: > > > > > > ># ifconfig -m cxgbe0 > > > >cxgbe0: flags=8943 > > > > > > ># ifconfig cxgbe0 mtu 9000 > > > >ifconfig: ioctl SIOCSIFMTU (set mtu): Invalid argument > > > > > > I believe this device, like many others, does not allow the MTU (or > > > actually the MRU) to be changed once the receive ring has been set up > > > > This is not correct. You can change the MTU of a cxgbe/cxl interface at > > any time (whether it's up or down, passing traffic or idle, etc.). > > > For some reason the stack needs init to be called when the MTU is changed > for it to actually change the size of the packets passed to the driver. At > least cxgb does not do that. I'm not at my computer right now, but cxgbe > may be the same. If that's the case just up / down the interface. It _will_ > take effect without that if it's passed at module load. The problem that was reported was that the ioctl that sets the MTU failed, not that the ioctl succeeded but the MTU change did not take effect. Regards, Navdeep