From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: measuring and/or dealing with "idleness" and variable frequency Date: Mon, 10 Jun 2013 16:33:20 -0600 Message-ID: <51B65430.8050501@gmail.com> References: <51B0CADF.8040508@hp.com> <51B3F4A3.3020502@gmail.com> <51B63847.1010008@hp.com> <51B652F9.4020402@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f171.google.com ([209.85.192.171]:55300 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752096Ab3FJWdd (ORCPT ); Mon, 10 Jun 2013 18:33:33 -0400 Received: by mail-pd0-f171.google.com with SMTP id y14so5031242pdi.16 for ; Mon, 10 Jun 2013 15:33:33 -0700 (PDT) In-Reply-To: <51B652F9.4020402@hp.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Rick Jones Cc: linux-perf-users@vger.kernel.org On 6/10/13 4:28 PM, Rick Jones wrote: >> I think I could get what I want from that - assuming I could get that to >> a kernel I can use in my test env, but am guessing it is rather more >> than I"m looking for at the moment. I'm wondering if there might be a >> simpler way to go - just get the idle loop to keep looping rather than >> halt (?) the thread, so there would still be cycle events in the PMU? >> (And perhaps set the system to a static, high-performance mode to avoid >> frequency changes and maybe even disable HT?) > > Or, after having found > https://www.kernel.org/doc/Documentation/kernel-parameters.txt, perhaps > idle=poll? Yes, that should turn the server into a power-sucking space heater and keep the cycles counter firing. David