From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: Re: [PATCH 2/2 net-next] tcp: sk_add_backlog() is too agressive for TCP Date: Tue, 24 Apr 2012 10:25:39 -0500 (CDT) Message-ID: References: <1335173934.3293.84.camel@edumazet-glaptop> <4F958DFD.7010207@hp.com> <1335201795.5205.35.camel@edumazet-glaptop> <20120423.160149.1515408777176168288.davem@davemloft.net> <1335213446.5205.65.camel@edumazet-glaptop> <4F95C22D.3010908@hp.com> <1335216631.5205.71.camel@edumazet-glaptop> <4F95CECF.6030901@hp.com> <1335218707.5205.87.camel@edumazet-glaptop> <4F95D4CA.7020005@hp.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Eric Dumazet , David Miller , netdev@vger.kernel.org, therbert@google.com, ncardwell@google.com, maze@google.com, ycheng@google.com, ilpo.jarvinen@helsinki.fi To: Rick Jones Return-path: Received: from smtp103.prem.mail.ac4.yahoo.com ([76.13.13.42]:45695 "HELO smtp103.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755299Ab2DXPZn (ORCPT ); Tue, 24 Apr 2012 11:25:43 -0400 In-Reply-To: <4F95D4CA.7020005@hp.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 23 Apr 2012, Rick Jones wrote: > Is it at all possible to have the copies happen without the connection being > locked? If indeed it is possible to be held-off with the connection locked > for the better part of 3/4 of a millisecond, just what will that do to 40 or > 100 GbE? If you've been seeing queues of 300 ACKs at 10 GbE that would be > 3000 at 100 GbE, and assuming those are all in a 2048 byte buffer thats 6MB > just of ACKs. I suppose 100GbE does mean non-trivial quantities of buffering > anyway but that does still seem rather high. At some point people will need to realize that it is not business as usual if one tries to use the current network porotocols at speeds above 1G. There is a reason for high speed networks implementing new protocols like RDMA techniques and lossless characteristics of a network.