From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lennert Buytenhek Subject: Re: via-rhine unable to send back-to-back packets? Date: Tue, 30 Nov 2004 07:48:23 +0100 Message-ID: <20041130064823.GA27872@xi.wantstofly.org> References: <20041129222700.GA22918@xi.wantstofly.org> <20041129172540.6b959858.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: rl@hellgate.ch, netdev@oss.sgi.com Return-path: To: "David S. Miller" Content-Disposition: inline In-Reply-To: <20041129172540.6b959858.davem@davemloft.net> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Mon, Nov 29, 2004 at 05:25:40PM -0800, David S. Miller wrote: > > For example, when transmitting 300-byte packets, I can TX 38261 packets > > per second, but I should be able to TX ~38580. When doing the math, it > > turns out that 38261 is exactly the number of 302-byte packets you can > > stuff into Fast Ethernet per second. > > Is the packet length in those calculations taking into consideration > the CRC et al. bytes that the card adds to the packet? Yeah, preamble (8 bytes), CRC (4 bytes), inter-packet gap (12 bytes). Perhaps the via-rhine simply can't send out packets back-to-back and needs 14 byte times of inter-packet gap. I couldn't find any stray +2 in the driver anywhere but I'm just checking.