From mboxrd@z Thu Jan 1 00:00:00 1970 From: thomas yang Subject: Re: Ethernet CRC questions Date: Wed, 30 Dec 2009 13:53:09 +0800 Message-ID: References: <1262108376.5941.5.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Ben Hutchings Return-path: Received: from mail-pz0-f171.google.com ([209.85.222.171]:60763 "EHLO mail-pz0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053AbZL3FxK convert rfc822-to-8bit (ORCPT ); Wed, 30 Dec 2009 00:53:10 -0500 Received: by pzk1 with SMTP id 1so3888780pzk.33 for ; Tue, 29 Dec 2009 21:53:09 -0800 (PST) In-Reply-To: <1262108376.5941.5.camel@localhost> Sender: netdev-owner@vger.kernel.org List-ID: 2009/12/30 Ben Hutchings : > On Wed, 2009-12-30 at 01:17 +0800, thomas yang wrote: >> How does Linux =A0generate Ethernet CRC ? >> by the hardware (Ethernet controller) =A0or =A0use crc32_le() / >> crc32_be() =A0 =A0 ( lib/crc32.c ) =A0? >> >> P.S. =A0 my =A0network card is =A0rtl8139d =A0, use =A08139too drive= r > > The Ethernet frame CRC is normally generated and verified in hardware= =2E > These library functions are needed for the few MACs that don't, or wh= ere > the same CRC function is used for some other purpose (e.g. as a hash > function for multicast filtering). > Does the Ethernet frame CRC (generate and verify in hardware) make the TX / RX rate a little smaller , and a longer end-to-end delay ? Could I disable CRC appending / verifying in the network card driver on all of my nodes (machines) ? Thanks. -- Thomas