From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eli Cohen Subject: dropped packets when IP forwarding Date: Mon, 3 May 2010 18:31:54 +0300 Message-ID: <20100503153154.GB5734@mtldesk030.lab.mtl.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline Sender: linux-net-owner@vger.kernel.org To: linux-net@vger.kernel.org, Linux RDMA list List-Id: linux-rdma@vger.kernel.org Hi, I am trying to check the forwarding rate between two net devices on my machine. What I see is that when the rate gets higher than some thresohld, the reception rate can still increase but the trasnmit rate reaches a maximum. At this point I assume packets get dropped. When looking at the CPU utilization I see that they're around 50% so the CPUs can do work. I also see that the trasmit queue is not stopped so I think that maybe the IP layer drops them (lack of buffers?). Does anyone have an idea?