From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0811035558717815484==" MIME-Version: 1.0 From: Igor Zhbanov Subject: Re: [Powertop] Powertop doesn't detects sleeping ARM cores Date: Thu, 20 Sep 2012 13:57:10 +0400 Message-ID: <505AE876.4080105@samsung.com> In-Reply-To: 20120920094354.GB3237@swordfish.minsk.epam.com To: powertop@lists.01.org List-ID: --===============0811035558717815484== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sergey Senozhatsky wrote: > On (09/20/12 13:29), Igor Zhbanov wrote: >>> On (09/20/12 12:24), Igor Zhbanov wrote: >>>> Chris Ferron wrote: >>>> >>>> Now I'm looking for solution. But I see now only four ways: >>>> >>>> 1) Develop another kernel mechanism for providing information about al= l available >>>> CPUs and cores. Or ask the kernel authors not to remove offline co= res from >>>> /proc/cpuinfo and their information files from /sys/.../cpu/. >>> procps (e.g. top utility) use sysconf _SC_NPROCESSORS_CONF/_SC_NPROCESS= ORS_ONLN for >>> that purpose. >>> >>> https://www.gnu.org/software/libc/manual/html_node/Processor-Resources.= html >> Counting of the CPUs is the least problem. (By the way, how sysconf() fi= gures >> out the number? I suppose that it reads /proc/cpuinfo of scans /sys/. >> Is there any other way?). >> >> The problem is that the PowerTOP needs to read information about cores >> from the files in /sys/.../cpu/cpuX/ directory (about C- and P-states, s= iblings >> etc). And needed files in these directories are present only for cores >> which are currently online. > right, I was thinking about that some time ago: and from the top of my he= ad kind of a solution > seemed to be to track number of CPUs before measure, compare with the pre= viously known one, > and "re-init" powertop (at least rebuild CPUs part), but it's not that of= ten that I offline/online > CPUs, so I decided to drop it. with ARM we have a different story. > > on x86(_64) "dirty" CPU offline support looks "easy", just make get_msr()= error non-fatal. > online -- that's the problem, agree. Perhaps PowerTOP could wake up every core in its calibration phase and stor= y collected information in platform config file. -- = Best regards, Igor Zhbanov, Expert Software Engineer, phone: +7 (495) 797 25 00 ext 3806 e-mail: i.zhbanov(a)samsung.com ASWG, Moscow R&D center, Samsung Electronics 12 Dvintsev street, building 1 127018, Moscow, Russian Federation --===============0811035558717815484==--