From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============2253136277143962835==" MIME-Version: 1.0 From: Sergey Senozhatsky Subject: Re: [Powertop] Powertop doesn't detects sleeping ARM cores Date: Thu, 20 Sep 2012 12:14:33 +0300 Message-ID: <20120920091433.GA3237@swordfish.minsk.epam.com> In-Reply-To: 505AD2D0.10505@samsung.com To: powertop@lists.01.org List-ID: --===============2253136277143962835== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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 all a= vailable > CPUs and cores. Or ask the kernel authors not to remove offline cores = from > /proc/cpuinfo and their information files from /sys/.../cpu/. procps (e.g. top utility) use sysconf _SC_NPROCESSORS_CONF/_SC_NPROCESSORS_= ONLN for that purpose. https://www.gnu.org/software/libc/manual/html_node/Processor-Resources.html -ss > 2) Scan /sys/.../cpu for all CPUs and temporarily wake it up to gather in= formation. > 3) Ask the user to run PowerTOP on a heavy loaded system for the first ti= me > (or wake up all CPUs by the PowerTOP) and store collected CPU informat= ion somewhere > in /var/cache/powertop and reuse it on later runs. > 4) Don't just sleep in a main cycle, but scan /sys/.../cpu for new CPUs t= o appear. > (Perhaps there could be something like D-Bus or netlink notification w= hen a core > brought online -- I don't know about it). > = > At your personal view, what way fits better in the PowerTOP project? > = > P.S. This may be the case for x86 CPUs too. I have disable CPU2 by writing > to /sys/devices/system/cpu2/online, and the PowerTOP sees only CPU0, CPU1= , and CPU3. > Although default PC's CPU governor as I know doesn't turn off CPUs freque= ntly. >=20 --===============2253136277143962835==--