Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754903AbbDTLDF (ORCPT ); Mon, 20 Apr 2015 07:03:05 -0400 Received: from mail-oi0-f43.google.com ([209.85.218.43]:36585 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754640AbbDTLDD (ORCPT ); Mon, 20 Apr 2015 07:03:03 -0400 MIME-Version: 1.0 In-Reply-To: <1429188136.7346.198.camel@edumazet-glaptop2.roam.corp.google.com> References: <1428596218.25985.263.camel@edumazet-glaptop2.roam.corp.google.com> <1428932970.3834.4.camel@edumazet-glaptop2.roam.corp.google.com> <1429115934.7346.107.camel@edumazet-glaptop2.roam.corp.google.com> <552E9E8D.1080000@eu.citrix.com> <1429118948.7346.114.camel@edumazet-glaptop2.roam.corp.google.com> <552EA2BC.5000707@eu.citrix.com> <1429120373.7346.125.camel@edumazet-glaptop2.roam.corp.google.com> <552EA844.5010308@eu.citrix.com> <1429121979.7346.138.camel@edumazet-glaptop2.roam.corp.google.com> <552F7936.9070205@eu.citrix.com> <552F7EF4.9030107@iogearbox.net> <552F887A.4060708@eu.citrix.com> <1429188136.7346.198.camel@edumazet-glaptop2.roam.corp.google.com> Date: Mon, 20 Apr 2015 12:03:02 +0100 X-Google-Sender-Auth: Zb9NLNAnM3uLOw4fPShFIC0frX8 Message-ID: Subject: Re: [Xen-devel] "tcp: refine TSO autosizing" causes performance regression on Xen From: George Dunlap To: Eric Dumazet Cc: Jonathan Davies , "xen-devel@lists.xensource.com" , Wei Liu , Ian Campbell , Daniel Borkmann , Stefano Stabellini , netdev , Linux Kernel Mailing List , Eric Dumazet , Paul Durrant , linux-arm-kernel@lists.infradead.org, Felipe Franciosi , Christoffer Dall , David Vrabel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1049 Lines: 26 On Thu, Apr 16, 2015 at 1:42 PM, Eric Dumazet wrote: > On Thu, 2015-04-16 at 11:01 +0100, George Dunlap wrote: > >> He suggested that after he'd been prodded by 4 more e-mails in which two >> of us guessed what he was trying to get at. That's what I was >> complaining about. > > My big complain is that I suggested to test to double the sysctl, which > gave good results. > > Then you provided a patch using a 8x factor. How does that sound ? > > Next time I ask a raise, I should try a 8x factor as well, who knows, > it might be accepted. I see. I chose the value that Stefano had determined had completely eliminated the overhead. Doubling the value reduces the overhead to 8%, which should be fine for a short-term fix while we git a proper mid/long-term fix. -George -- 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/