Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751870AbaBHONk (ORCPT ); Sat, 8 Feb 2014 09:13:40 -0500 Received: from mail-pb0-f51.google.com ([209.85.160.51]:35480 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751193AbaBHONi (ORCPT ); Sat, 8 Feb 2014 09:13:38 -0500 Message-ID: <1391868816.10160.93.camel@edumazet-glaptop2.roam.corp.google.com> Subject: Re: REGRESSION f54b311142a92ea2e42598e347b84e1655caf8e3 tcp auto corking slows down iSCSI file system creation by factor of 70 [WAS: 4 TB VMFS creation takes 15 minutes vs 26 seconds] From: Eric Dumazet To: Thomas Glanzmann Cc: John Ogness , Eric Dumazet , "David S. Miller" , "Nicholas A. Bellinger" , target-devel , Linux Network Development , LKML Date: Sat, 08 Feb 2014 06:13:36 -0800 In-Reply-To: <1391867404.10160.88.camel@edumazet-glaptop2.roam.corp.google.com> References: <20140206153640.GB4103@glanzmann.de> <1391727771.14985.41.camel@haakon3.risingtidesystems.com> <20140207051500.GB10916@glanzmann.de> <20140207075536.GB17815@glanzmann.de> <1391801597.1155.28.camel@haakon3.risingtidesystems.com> <20140207205142.GA8609@glanzmann.de> <20140208093808.GD16336@glanzmann.de> <1391865273.10160.76.camel@edumazet-glaptop2.roam.corp.google.com> <1391866389.10160.80.camel@edumazet-glaptop2.roam.corp.google.com> <1391867404.10160.88.camel@edumazet-glaptop2.roam.corp.google.com> 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 Sat, 2014-02-08 at 05:50 -0800, Eric Dumazet wrote: > On Sat, 2014-02-08 at 05:33 -0800, Eric Dumazet wrote: > > On Sat, 2014-02-08 at 05:14 -0800, Eric Dumazet wrote: > > > Here is the combined patch, could you test it ? > > > > Also make sure you have commit a181ceb501b31b4bf8812a5c84c716cc31d82c2d > > ("tcp: autocork should not hold first packet in write queue") > > in your tree. > > > > > > BTW this problem demonstrates there is room for improvement in iCSCI, > using MSG_MORE to avoid sending two small segments in separate frames. > > [1] 00:32:35.726568 IP 10.101.99.5.3260 > 10.101.0.13.27778: Flags [P.], seq 145:193, ack 144, win 235, options [nop,nop,TS val 4294960733 ecr 385385], length 48 > [2] 00:32:35.838074 IP 10.101.0.13.27778 > 10.101.99.5.3260: Flags [.], ack 193, win 514, options [nop,nop,TS val 385396 ecr 4294960733], length 0 > [3] 00:32:35.838099 IP 10.101.99.5.3260 > 10.101.0.13.27778: Flags [P.], seq 193:705, ack 144, win 235, options [nop,nop,TS val 4294960761 ecr 385396], length 512 > > [1] & [3] could be coalesced, and [2] would be avoided. > With the fix, new pcap is more explicit about this suboptimal behavior : 05:34:16.280900 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [.], ack 54353, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 0 05:34:16.280949 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [P.], seq 5328:5376, ack 54353, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 48 05:34:16.280982 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 54353:54401, ack 5376, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 48 05:34:16.281000 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 54401:54913, ack 5376, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 512 05:34:16.281107 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [.], ack 54913, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 0 05:34:16.281157 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [P.], seq 5376:5424, ack 54913, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 48 05:34:16.281190 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 54913:54961, ack 5424, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 48 05:34:16.281208 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 54961:55473, ack 5424, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 512 05:34:16.281337 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [.], ack 55473, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 0 05:34:16.281390 IP 10.101.0.13.41531 > 10.101.99.5.3260: Flags [P.], seq 5424:5472, ack 55473, win 514, options [nop,nop,TS val 1732452 ecr 4294935370], length 48 05:34:16.281423 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 55473:55521, ack 5472, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 48 05:34:16.281440 IP 10.101.99.5.3260 > 10.101.0.13.41531: Flags [P.], seq 55521:56033, ack 5472, win 235, options [nop,nop,TS val 4294935370 ecr 1732452], length 512 -- 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/