Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753385AbaBJVOt (ORCPT ); Mon, 10 Feb 2014 16:14:49 -0500 Received: from infra.glanzmann.de ([88.198.249.254]:35363 "EHLO infra.glanzmann.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752984AbaBJVOr (ORCPT ); Mon, 10 Feb 2014 16:14:47 -0500 Date: Mon, 10 Feb 2014 22:14:45 +0100 From: Thomas Glanzmann To: Eric Dumazet Cc: "Nicholas A. Bellinger" , John Ogness , Eric Dumazet , "David S. Miller" , target-devel , Linux Network Development , LKML Subject: Re: [PATCH] This extends tx_data and and iscsit_do_tx_data with the additional parameter flags and avoids sending multiple TCP packets in iscsit_fe_sendpage_sg Message-ID: <20140210211445.GE19621@glanzmann.de> Mail-Followup-To: Eric Dumazet , "Nicholas A. Bellinger" , John Ogness , Eric Dumazet , "David S. Miller" , target-devel , Linux Network Development , LKML References: <20140208165732.GB22359@glanzmann.de> <1391879318.10160.108.camel@edumazet-glaptop2.roam.corp.google.com> <20140208171531.GA23798@glanzmann.de> <1391886759.10160.114.camel@edumazet-glaptop2.roam.corp.google.com> <20140209074027.GA8105@glanzmann.de> <20140209074227.GA8219@glanzmann.de> <1391949039.10160.129.camel@edumazet-glaptop2.roam.corp.google.com> <1392058718.17867.8.camel@haakon3.risingtidesystems.com> <20140210205634.GC19621@glanzmann.de> <1392066100.6615.55.camel@edumazet-glaptop2.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1392066100.6615.55.camel@edumazet-glaptop2.roam.corp.google.com> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Eric, > Hmm.. I was not aware of high RTT for some packets. > Can you spot this on the pcap you provided ? with the latest patch as in: (node-62) [~/work/linux-2.6] git diff | pbot http://pbot.rmdir.de/CQwqI6b7wJProw_xaukmEg with net.ipv4.tcp_min_tso_segs=2 we had this pcap: https://thomas.glanzmann.de/tmp/tcp_auto_corking_on_patched_tcp_more_notlast.pcap.bz2 And here is the RTT TCP graph: Wireshark > Statistics > TCP Stream Graph > Round Trip Time Graph https://thomas.glanzmann.de/tmp/screenshot-mini-2014-02-10-22_04_30.png with net.ipv4.tcp_min_tso_segs=8 we have this pcap: https://thomas.glanzmann.de/tmp/tcp_auto_corking_on_patched_tcp_more_notlast_min_tso_segs_8.pcap.bz2 And here is the RTT TCP graph: Wireshark > Statistics > TCP Stream Graph > Round Trip Time Graph This gives us 0.0015 seconds RTT (1.5 ms) Without TCP autocorking we had 0.0005 (0.5 ms). https://thomas.glanzmann.de/tmp/screenshot-mini-2014-02-08-09:53:17.png Cheers, Thomas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/