From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764186Ab3DDHhO (ORCPT ); Thu, 4 Apr 2013 03:37:14 -0400 Received: from mail-bk0-f44.google.com ([209.85.214.44]:34397 "EHLO mail-bk0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763314Ab3DDHhK (ORCPT ); Thu, 4 Apr 2013 03:37:10 -0400 Date: Thu, 4 Apr 2013 09:37:00 +0200 From: Richard Cochran To: John Stultz Cc: Pawel Moll , Peter Zijlstra , David Ahern , Stephane Eranian , Thomas Gleixner , LKML , "mingo@elte.hu" , Paul Mackerras , Anton Blanchard , Will Deacon , "ak@linux.intel.com" , Pekka Enberg , Steven Rostedt , Robert Richter Subject: Re: [RFC] perf: need to expose sched_clock to correlate user samples with kernel samples Message-ID: <20130404073700.GA1860@localhost.localdomain> References: <1363291021.3100.144.camel@hornet> <51586315.7080006@gmail.com> <5159D221.70304@linaro.org> <1364889256.16858.1.camel@laptop> <515B0502.8070408@linaro.org> <1365009558.26858.19.camel@hornet> <515C66FE.7030501@linaro.org> <1365010502.26858.32.camel@hornet> <515C6C01.9070905@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <515C6C01.9070905@linaro.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 03, 2013 at 10:50:57AM -0700, John Stultz wrote: > > I get the reasoning around reusing the fd we already have, but is > the possibility of a dynamic chardev pathname really a big concern? I have been following this thread, and, not knowing very much about perf, I would think that the userland can easily open a second file (the dynamic posix clock chardev) in order to get these time stamps. > Maybe can we extend the dynamic posix clock code to work on more > then just the chardev? Although I worry about multiplexing too much > functionality on the file. I don't yet see a need for that, but if we do, then it should work in a generic way, and not as a list of special cases, like we saw in the patch. Thanks, Richard