From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: Netchannles: first stage has been completed. Further ideas. Date: Fri, 21 Jul 2006 09:26:42 -0700 Message-ID: <44C10042.1020503@hp.com> References: <20060720164100.GA9213@ms2.inr.ac.ru> <20060720210849.GA28715@tservice.net.ru> <20060720225908.GA18362@ms2.inr.ac.ru> <20060720.215504.41641534.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: kuznet@ms2.inr.ac.ru, johnpol@2ka.mipt.ru, netdev@vger.kernel.org Return-path: Received: from palrel10.hp.com ([156.153.255.245]:61402 "EHLO palrel10.hp.com") by vger.kernel.org with ESMTP id S1751073AbWGUQ0q (ORCPT ); Fri, 21 Jul 2006 12:26:46 -0400 To: David Miller In-Reply-To: <20060720.215504.41641534.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > All this talk reminds me of one thing, how expensive tcp_ack() is. > And this expense has nothing to do with TCP really. The main cost is > purging and freeing up the skbs which have been ACK'd in the > retransmit queue. > > So tcp_ack() sort of inherits the cost of freeing a bunch of SKBs > which haven't been touched by the cpu in some time and are thus nearly > guarenteed to be cold in the cache. > > This is the kind of work we could think about batching to user > sleeping on some socket call. Ultimately isn't that just trying to squeeze the balloon? rick jones nice to see people seeing ACKs as expensive though :)