From mboxrd@z Thu Jan 1 00:00:00 1970 From: josh@joshtriplett.org Subject: Re: [PATCH 08/24] net, diet: Make TCP metrics optional Date: Tue, 6 May 2014 10:30:15 -0700 Message-ID: <20140506173015.GC20776@cloud> References: <1399328773-6531-9-git-send-email-andi@firstfloor.org> <20140505.231229.136734008603421707.davem@davemloft.net> <20140506032114.GP2382@two.firstfloor.org> <20140505.232327.578134514220748085.davem@davemloft.net> <20140506155703.GA20391@cloud> <1399394359.15399.20.camel@edumazet-glaptop2.roam.corp.google.com> <20140506164546.GB20536@cloud> <1399395804.15399.27.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , andi@firstfloor.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, tom.zanussi@linux.intel.com, ak@linux.intel.com To: Eric Dumazet Return-path: Received: from relay4-d.mail.gandi.net ([217.70.183.196]:34717 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750748AbaEFRaU (ORCPT ); Tue, 6 May 2014 13:30:20 -0400 Content-Disposition: inline In-Reply-To: <1399395804.15399.27.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, May 06, 2014 at 10:03:24AM -0700, Eric Dumazet wrote: > On Tue, 2014-05-06 at 09:45 -0700, josh@joshtriplett.org wrote: > > > Sounds like we have some optimization to do, then; there's no > > fundamental unfixable reason for that delta. > > I think you have little idea of the reasons for this delta. I have a rather good idea, actually. > Some servers handle 10 millions of TCP flows, using as little as 1KB per > connection in user space, all included. > > Do you have an idea of how much memory is needed for 10 millions TCP > sockets in the kernel ? Too much. That's potentially fixable, but not if we start with the premise that it's impossible. - Josh Triplett