Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756444Ab0DFCQM (ORCPT ); Mon, 5 Apr 2010 22:16:12 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:48097 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757090Ab0DFCQD (ORCPT ); Mon, 5 Apr 2010 22:16:03 -0400 Date: Tue, 6 Apr 2010 07:45:59 +0530 From: Balbir Singh To: Paul Menage Cc: Mike Chan , cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] sched: cpuacct: Track cpuusage per cpu frequency Message-ID: <20100406021559.GD3630@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <1270496004-9715-1-git-send-email-mike@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1510 Lines: 35 * menage@google.com [2010-04-05 12:52:57]: > On Mon, Apr 5, 2010 at 12:33 PM, Mike Chan wrote: > > New file: cpuacct.cpufreq when CONFIG_CPU_FREQ_STATS is enabled. > > > > cpuacct.cpufreq accounts for cpu time per-cpu frequency, time is exported > > in nano-seconds > > Can you clarify the wording of this (and describe it in the relevant > Documentation/... file)? It's not clear. > > From the code, it appears that the file reports a breakdown of how > much CPU time the cgroup has been consuming at each different CPU > frequency level. If so, then you probably want to reword the > description to avoid "per-cpu", since that makes it sounds as though > it's reporting something, well, "per CPU". > > Also, what's the motivation here? If it's for power monitoring > purposes, might it be simpler to just report a single number, that's > the integral of the CPU usage by frequency index (i.e. calculated from > the same information that this patch is already gathering in > cpuacct_charge()) rather than dumping a whole table on userspace? As utilization increases, won't the integral quickly overflow? BTW, Mike have you looked at the scaled accounting infrastructure we have in taskstats? -- Three Cheers, Balbir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/