From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [PATCH net-next] tcp: reduce memory needs of out of order queue Date: Mon, 17 Oct 2011 09:47:44 -0700 Message-ID: <4E9C5C30.1040804@hp.com> References: <1318576791.2533.99.camel@edumazet-laptop> <20111014.034224.1197576516015404466.davem@davemloft.net> <4E985A3F.5080103@hp.com> <4E98B3B4.20406@hp.com> <1318660775.2525.29.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from g4t0014.houston.hp.com ([15.201.24.17]:31460 "EHLO g4t0014.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751951Ab1JQQrq (ORCPT ); Mon, 17 Oct 2011 12:47:46 -0400 In-Reply-To: <1318660775.2525.29.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: > > Rick, could you redo the test, using following bit on receiver : > > echo 1>/proc/sys/net/ipv4/tcp_adv_win_scale raj@tardy:~/netperf2_trunk$ netstat -s > before; src/netperf -H raj-8510w.americas.hpqcorp.net -t tcp_rr -- -b 256 -D -o throughput,local_transport_retrans,remote_transport_retrans,lss_size_end,rsr_size_end ; netstat -s > afterMIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to internal-host.americas.hpqcorp.net (16.89.245.115) port 0 AF_INET : nodelay : first burst 256 Throughput,Local Transport Retransmissions,Remote Transport Retransmissions,Local Send Socket Size Final,Remote Recv Socket Size Final 78527.68,289,0,16384,98304 Deltas on the receiver: TcpExt: 27 packets pruned from receive queue because of socket buffer overrun 0 TCP sockets finished time wait in fast timer 0 delayed acks sent 0 delayed acks further delayed because of locked socket Quick ack mode was activated 0 times 19 packets directly queued to recvmsg prequeue. 0 bytes directly in process context from backlog 670 bytes directly received in process context from prequeue 739983 packet headers predicted 14 packets header predicted and directly queued to user 127 acknowledgments not containing data payload received 235774 predicted acknowledgments 0 other TCP timeouts 6553 packets collapsed in receive queue due to low socket buffer 0 DSACKs sent for old packets TCPBacklogDrop: 294 So, moving on to: > If you still have collapses/retransmits, you then could try : > > echo -2>/proc/sys/net/ipv4/tcp_adv_win_scale raj@tardy:~/netperf2_trunk$ netstat -s > before; src/netperf -H raj-8510w.americas.hpqcorp.net -t tcp_rr -- -b 256 -D -o throughput,local_transport_retrans,remote_transport_retrans,lss_size_end,rsr_size_end ; netstat -s > after MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to internal-host.americas.hpqcorp.net (16.89.245.115) port 0 AF_INET : nodelay : first burst 256 Throughput,Local Transport Retransmissions,Remote Transport Retransmissions,Local Send Socket Size Final,Remote Recv Socket Size Final 95981.83,0,0,121200,156600 No retransmissions in that one. rick