From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Fink Subject: Re: [PATCH] tcp: SO_TIMESTAMP implementation for TCP Date: Sat, 1 May 2010 01:07:35 -0400 Message-ID: <20100501010735.dfe097bc.billfink@mindspring.com> References: <20100429.233958.212393607.davem@davemloft.net> <20100430.164115.257514715.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: therbert@google.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from elasmtp-masked.atl.sa.earthlink.net ([209.86.89.68]:45345 "EHLO elasmtp-masked.atl.sa.earthlink.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877Ab0EAFHk (ORCPT ); Sat, 1 May 2010 01:07:40 -0400 In-Reply-To: <20100430.164115.257514715.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 30 Apr 2010, David Miller wrote: > From: Tom Herbert > Date: Fri, 30 Apr 2010 00:58:32 -0700 > > >> All these new checks and branches for a feature of questionable value. > > > >> If you can modify you apps to grab this information you can also probe > >> for the information using external probing tools. > >> > > I don't see an nice way to do that, we're profiling a significant > > percentage of millions of connections over thousands of paths as part > > of standard operations while incurring negligible overhead. The app > > can can easily timestamp its operations, but without some mechanism > > for getting timestamps out of a TCP connection, the networking portion > > of servicing requests is pretty much a black box in that. > > If other people have an opinion about this, now would be the time > to speak up. :-) Not being a kernel hacker, I will naively ask if the kernel tracing facility could somehow be used to provide the desired info (or could be modified to provide it). -Bill