From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: Questions about sleep states on ARM Juno R0 Date: Wed, 16 Mar 2016 16:51:28 +0000 Message-ID: <56E98F10.2030804@arm.com> References: <56E80519.1040400@bsc.es> <56E98711.801@bsc.es> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:43696 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933053AbcCPQvc (ORCPT ); Wed, 16 Mar 2016 12:51:32 -0400 In-Reply-To: <56E98711.801@bsc.es> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: nishtala Cc: Sudeep Holla , Linux PM list , Punit Agrawal On 16/03/16 16:17, nishtala wrote: > Thanks for your reply. I have one more question. > > I ran a single instance of blackscholes (compute bounded > application) with 4 threads on 4 small cores at 0.65GHz > and then I ran it on 1 big core at 0.6GHz. > > The power as read from the 4 energy registers shows that the > 1Big core at 0.6GHz consumes as much power as 4 small cores at 0.65GHz. > Do this power proportionality number make sense? > Yes that seems sensible. >>> - When the system is idle, that is, no user initiated tasks are >>> running; I >>> expected the counter for "usage" in CLUSTER_SLEEP_0 to remain constant, >>> because you don't exit >>> until any kernel interrupts occur, and is guaranteed to stay atleast for >>> 3500us while the "time" in the same category to increase. >>> >> Are you not seeing any increase in interrupt count on that cpu where >> CLUSTER_SLEEP_0 usage is increasing. Also there's not guarantee that >> it will stay in CLUSTER_SLEEP_0 for 3500us, it can be woken up by >> interrupts. > Yes, the interrupt count is also increasing. That explains. >>> - When I run an application only on small OR big cores, the counter >>> "usage" >>> for CPU_SLEEP_0 on the other type of core (big/small) still isn't >>> updated. >>> Am I missing something here? >>> >> Is this a question or your observation ? You are assuming that only your >> applications will be running ? It depends also on several background >> tasks >> that are running. > it is a question, but i believe that background tasks are running Yes >> [...] >> >>> WARNING / LEGAL TEXT: This message is intended only for the use of the >>> individual or entity to which it is addressed and may contain >>> information which is privileged, confidential, proprietary, or exempt >>> from disclosure under applicable law. If you are not the intended >>> recipient or the person responsible for delivering the message to the >>> intended recipient, you are strictly prohibited from disclosing, >>> distributing, copying, or in any way using this message. If you have >>> received this communication in error, please notify the sender and >>> destroy and delete any copies you may have received. >>> >> You need to fix this, please get rid of this disclaimer if you want >> people to respond to you. > > I unticked add signature in my mail client. Hope it works now. > > > WARNING / LEGAL TEXT: This message is intended only for the use of the > individual or entity to which it is addressed and may contain > information which is privileged, confidential, proprietary, or exempt > from disclosure under applicable law. If you are not the intended > recipient or the person responsible for delivering the message to the > intended recipient, you are strictly prohibited from disclosing, > distributing, copying, or in any way using this message. If you have > received this communication in error, please notify the sender and > destroy and delete any copies you may have received. > > http://www.bsc.es/disclaimer > Unfortunately, not yet. -- Regards, Sudeep