From owner-freebsd-net@FreeBSD.ORG Tue May 8 04:35:35 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 382FA106566C; Tue, 8 May 2012 04:35:35 +0000 (UTC) (envelope-from jfvogel@gmail.com) Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com [209.85.212.170]) by mx1.freebsd.org (Postfix) with ESMTP id 944968FC0C; Tue, 8 May 2012 04:35:34 +0000 (UTC) Received: by wibhm4 with SMTP id hm4so206282wib.1 for ; Mon, 07 May 2012 21:35:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=E9GvXJNFRN4KXwtLX60aXGC3ERYa0hrJvSSpt0O0UcI=; b=ukihssEYTY0BD9bB8iGdwUhiupvBNwLGKIcLGD6ocizWEa3WcfvQONCJG6MEG9yHLP kJ18cvd/fjrNpCoQjS3mr/qw+rbntqykj7XnjSV9+ULfwS2l0HY4XMn4+GiQCPCG3kes G2BCxXFoboQ0WqWPEnJA4VDLAAimCbH6IjWW9WQEqjyC01tJEW8dQdL9AGwKWp4rucZK NFX9tzTJEkjMjLgq9vcnhKHKbCXMmyxZOYuKPpqBUPq28wPEyeRoWLK8YNzIu5NAPkO4 5eJdbyI6H/WvnGGuNVj70JDFVtAsFTJ6SasHANhOYTf0/fC97IR2QKqlsRYymhbnfN9/ 3YNw== MIME-Version: 1.0 Received: by 10.216.140.222 with SMTP id e72mr59923wej.69.1336451733650; Mon, 07 May 2012 21:35:33 -0700 (PDT) Received: by 10.180.7.103 with HTTP; Mon, 7 May 2012 21:35:33 -0700 (PDT) In-Reply-To: References: Date: Mon, 7 May 2012 21:35:33 -0700 Message-ID: From: Jack Vogel To: Juli Mallett Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-net@freebsd.org, Vijay Singh Subject: Re: What does adapter->stats.mpc[] report for ixgbe? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 May 2012 04:35:35 -0000 On Mon, May 7, 2012 at 5:31 PM, Juli Mallett wrote: > While we're on the subject, I've had some confusion for some time now: > > On Mon, May 7, 2012 at 5:25 PM, Jack Vogel wrote: > > Packets are missed when the receive FIFO has insufficient space to store > the > > incoming packet. > > This means the on-card FIFO, i.e. the fixed-size FIFO that is divided > into receive and transmit space by the driver, right? And the > separate "receive no buffers" counter records instances where the > packet made it to the card but there was no buffer associated with a > receive descriptor to write it to? That has been my interpretation of > the documentation and the numbers I've seen in practice, but I've seen > conflicting interpretations and would much rather hear it from the > horse's mouth :) > > Thanks, > Juli. > Gee, not sure if I like being called a horse :) But yes you are correct. When you have multiple traffic classes, as it is when you have DCB, then the packet buffer may be partitioned into up to 8 parts. This would let you seperate say FCOE and iSCSI from normal net traffic. But for now in FreeBSD its just one which is divided into 3 parts: TX, RX, and FDIR (flow director). Cheers, Jack