From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: RE: GRO aggregation Date: Tue, 11 Sep 2012 21:35:32 +0200 Message-ID: <1347392132.13103.663.camel@edumazet-glaptop> References: <504F4063.9030706@mellanox.com> ,<1347388396.13103.658.camel@edumazet-glaptop> <36F7E4A28C18BE4DB7C86058E7B607241E622022@MTRDAG01.mtl.com> ,<1347390113.13103.660.camel@edumazet-glaptop> <36F7E4A28C18BE4DB7C86058E7B607241E622083@MTRDAG01.mtl.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" To: Shlomo Pongratz Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:53460 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757379Ab2IKTfh (ORCPT ); Tue, 11 Sep 2012 15:35:37 -0400 Received: by eekc1 with SMTP id c1so722847eek.19 for ; Tue, 11 Sep 2012 12:35:36 -0700 (PDT) In-Reply-To: <36F7E4A28C18BE4DB7C86058E7B607241E622083@MTRDAG01.mtl.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2012-09-11 at 19:24 +0000, Shlomo Pongratz wrote: > > I see that in ixgbe the weight for the NAPI is 64 (netif_napi_add). So > if packets are arriving in high rate then an the CPU is fast enough to > collect the packets as they arrive, assuming packets continue to > arrives while the NAPI runs. Then it should have aggregate more. So we > will have less passes trough the stack. > As I said, _if_ your cpu was loaded by other stuff, then you would see biggest GRO packets. GRO is not : "We want to kill latency and have big packets just because its better" Its more like : If load is big enough, try to aggregate TCP frames in less skbs.