From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Paasch Subject: Re: [PATCH net-next] tcp: speedup tcp_fixup_rcvbuf() Date: Thu, 16 May 2013 09:06:20 +0200 Message-ID: <1697330.SmXeaasf9r@cpaasch-mac> References: <1368681955.3301.11.camel@edumazet-glaptop> Reply-To: christoph.paasch@uclouvain.be Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit To: Eric Dumazet , netdev Return-path: Received: from mail-ee0-f47.google.com ([74.125.83.47]:37337 "EHLO mail-ee0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753708Ab3EPHG1 (ORCPT ); Thu, 16 May 2013 03:06:27 -0400 Received: by mail-ee0-f47.google.com with SMTP id t10so1537262eei.20 for ; Thu, 16 May 2013 00:06:26 -0700 (PDT) In-Reply-To: <1368681955.3301.11.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: Hello Eric, On Wednesday 15 May 2013 22:25:55 Eric Dumazet wrote: > tcp_fixup_rcvbuf() contains a loop to estimate initial socket > rcv space needed for a given mss. With large MTU (like 64K on lo), > we can loop ~500 times and consume a lot of cpu cycles. > > perf top of 200 concurrent netperf -t TCP_CRR just out of curiosity, how do you run 200 concurrent netperfs? Is there an option as in iperf (-P) ? I did not find anything like this in the netperf-code. Thanks, Christoph -- IP Networking Lab --- http://inl.info.ucl.ac.be MultiPath TCP in the Linux Kernel --- http://multipath-tcp.org UCLouvain --