Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753403AbaBJVBq (ORCPT ); Mon, 10 Feb 2014 16:01:46 -0500 Received: from mail-pd0-f170.google.com ([209.85.192.170]:38781 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627AbaBJVBm (ORCPT ); Mon, 10 Feb 2014 16:01:42 -0500 Message-ID: <1392066100.6615.55.camel@edumazet-glaptop2.roam.corp.google.com> 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 From: Eric Dumazet To: Thomas Glanzmann Cc: "Nicholas A. Bellinger" , John Ogness , Eric Dumazet , "David S. Miller" , target-devel , Linux Network Development , LKML Date: Mon, 10 Feb 2014 13:01:40 -0800 In-Reply-To: <20140210205634.GC19621@glanzmann.de> References: <20140208150001.GI20512@glanzmann.de> <1391871986.10160.105.camel@edumazet-glaptop2.roam.corp.google.com> <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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-02-10 at 21:56 +0100, Thomas Glanzmann wrote: > Hello Nab, > > > This looks correct to me. Thomas, once your able to confirm please > > include your 'Tested-by' and I'll include for the next -rc3 PULL > > request. > > Eric is currently reviewing our latest iteration with MSG_MORE for > kernel_sendmsg and MSG_MORE | MSG_SENDPAGE_NOTLAST for sendpage. However > with the last iteration we had again a high RTT for some packets. But > than Eric let me tune net.ipv4.tcp_min_tso_segs to 8 and the RTT went > down to what it used before auto corking was enabled. At least almost. > Hmm.. I was not aware of high RTT for some packets. Can you spot this on the pcap you provided ? > I'm having a steep learning curve but Eric hopefully knows how to get > this back in check. Nevertheless the regression I saw are history > because I saw that Eric has submitted the patch to David S. Miller which > fixes the two bugs that killed the iSCSI performance when tcp auto > corking was on. So currently we're just optimizing to get the last 20% > or so out of it. Quite interesting. Especially how much bandwidth can be > saved by coalescing packets. It depends on the ratio payload/headers. The beginning of your pcap show a lot of 512 bytes requests, so for this kind of requests, the gain is huge (maybe 50%), but for 32K or 64K request, gain would be marginal. -- 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/