Re: P-States in Linux
"Sreenidhi BG" <[email protected]> 8 Sep 2004 10:32:56 -0000
| Newsgroups | gmane.linux.power-management.devel |
|---|---|
| Message-ID | <[email protected]> |
This is a multipart mime message --Next_1094639576---0-203.199.83.27-4432 Content-type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline <P>=0AHello Robert, <BR>=0A<BR>=0AI tried the 2.6.8 kernel and it worked fi= ne. I re-compiled the 2.6.8 kernel with Power Management enabled, and it mu= st be enabled in BIOS as well. <BR>=0AI enabled the P-State driver in the k= ernel and force the P-State by echoing either 1 or 0 to the /proc/acpi/proc= essor/performance proc entry. <BR>=0Aecho -n 1 >> /proc/acpi/processo= r/performance <BR>=0A<BR>=0ABut I observed that active State of the cpu wil= l change to P0 or P1 only if the above command is executed twice. Dont know= the reason. But I was able to force to different P-State and also see a ch= ange in the operating frequency in /proc/cpuinfo.<BR>=0A<BR>=0A<BR>=0ARegar= ds,<BR>=0ASreenidhi,<BR>=0A<BR>=0A<BR>=0AOn Fri, 03 Sep 2004 Robert Freund = wrote :<BR>=0A>Hi,<BR>=0A><BR>=0A>The kernel interface to control = cpu speed has changed I think. There is a<BR>=0A>kernel option "ena= ble acpi performance interface" (or similar), which should<BR>=0A>e= nable the old and deprecated interface (/proc/.../performance), but it<BR>= =0A>doesn't work. I have emailed the linux kernel mailing list about thi= s but<BR>=0A>nobody wants to fix this.<BR>=0A><BR>=0A>Instead, try= <BR>=0A>/sys/devices/system/cpu/cpu0/cpufreq<BR>=0A>There you will fi= nd several files the names of which are quite<BR>=0A>self-explainatory. = You can echo frequency values in khz to these files.<BR>=0A>It's easier = to use a cpu frequency daemon though, like cpufreqd or speedfreqd.<BR>=0A&g= t;They offer nice extra functionality, like keeping your cpu as cool as<BR>= =0A>possible (only raising clock speed when needed).<BR>=0A><BR>=0A&g= t;I need to put this on my webpage as well.<BR>=0A><BR>=0A>If you hav= e any more questions, just email me.<BR>=0A><BR>=0A>Robert<BR>=0A>= <BR>=0A>On Tue, 31 Aug 2004 14:56:17 +0200, "Sreenidhi BG"<BR>= =0A><[email protected]> said:<BR>=0A> ><BR>=0A>= > Hi,<BR>=0A> ><BR>=0A> > I recently bought a Pentium M IBM= thinkpad. It is running on Linux, SuSe<BR>=0A> > 9.1 with 2.6.4 kern= el.<BR>=0A> ><BR>=0A> > I dont see the "performance" = entry in my<BR>=0A> > "proc/acpi/processor/CPU0/performance"= ; interface.<BR>=0A> ><BR>=0A> > I have enabled the PowerManage= ment section in Linux Kernel, recompiled<BR>=0A> > and booted with my= new kernel. But still I dont see the "performance"<BR>=0A> &g= t; entry in my /proc interface.<BR>=0A> ><BR>=0A> > How can I f= orce my Laptop to operate at different cpufreq, say P1 ? how<BR>=0A> >= ; do U switch between P0 and P1 ? are there any APIs available ( I mean<BR>= =0A> > exported by the kernel or ACPI driver ) and How do I know at w= hat<BR>=0A> > frequency is my CPU running?<BR>=0A> ><BR>=0A>= > Any pointers to any utilities/resources will be of great help.<BR>=0A= > ><BR>=0A> > Regards,<BR>=0A> > Sreenidhi,<BR>=0A> &g= t;<BR>=0A> ><BR>=0A> ><BR>=0A> > ---<BR>=0A> > Nach= richt wurde webbasiert erstellt,<BR>=0A> > Angaben ueber Absender sin= d nicht verifiziert.<BR>=0A=0A</P>=0A<br><br>=0A<A target=3D"_blank" HREF= =3D"http://clients.rediff.com/signature/track_sig.asp"><IMG SRC=3D"http://a= ds.rediff.com/RealMedia/ads/adstream_nx.cgi/www.rediffmail.com/inbox.htm@Bo= ttom" BORDER=3D0 VSPACE=3D0 HSPACE=3D0></a>=0A --Next_1094639576---0-203.199.83.27-4432 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hello Robert, =0A=0AI tried the 2.6.8 kernel and it worked fine. I re-compi= led the 2.6.8 kernel with Power Management enabled, and it must be enabled = in BIOS as well. =0AI enabled the P-State driver in the kernel and force th= e P-State by echoing either 1 or 0 to the /proc/acpi/processor/performance = proc entry. =0Aecho -n 1 >> /proc/acpi/processor/performance =0A=0ABut I ob= served that active State of the cpu will change to P0 or P1 only if the abo= ve command is executed twice. Dont know the reason. But I was able to force= to different P-State and also see a change in the operating frequency in /= proc/cpuinfo.=0A=0A=0ARegards,=0ASreenidhi,=0A=0A=0AOn Fri, 03 Sep 2004 Rob= ert Freund wrote :=0A>Hi,=0A>=0A>The kernel interface to control cpu speed = has changed I think. There is a=0A>kernel option "enable acpi performance i= nterface" (or similar), which should=0A>enable the old and deprecated inter= face (/proc/.../performance), but it=0A>doesn't work. I have emailed the li= nux kernel mailing list about this but=0A>nobody wants to fix this.=0A>=0A>= Instead, try=0A>/sys/devices/system/cpu/cpu0/cpufreq=0A>There you will find= several files the names of which are quite=0A>self-explainatory. You can e= cho frequency values in khz to these files.=0A>It's easier to use a cpu fre= quency daemon though, like cpufreqd or speedfreqd.=0A>They offer nice extra= functionality, like keeping your cpu as cool as=0A>possible (only raising = clock speed when needed).=0A>=0A>I need to put this on my webpage as well.= =0A>=0A>If you have any more questions, just email me.=0A>=0A>Robert=0A>=0A= >On Tue, 31 Aug 2004 14:56:17 +0200, "Sreenidhi BG"=0A><sreenidhi_bg@rediff= mail.com> said:=0A> >=0A> > Hi,=0A> >=0A> > I recently bought a Pentium M I= BM thinkpad. It is running on Linux, SuSe=0A> > 9.1 with 2.6.4 kernel.=0A> = >=0A> > I dont see the "performance" entry in my=0A> > "proc/acpi/processor= /CPU0/performance" interface.=0A> >=0A> > I have enabled the PowerManagemen= t section in Linux Kernel, recompiled=0A> > and booted with my new kernel. = But still I dont see the "performance"=0A> > entry in my /proc interface.= =0A> >=0A> > How can I force my Laptop to operate at different cpufreq, say= P1 ? how=0A> > do U switch between P0 and P1 ? are there any APIs availabl= e ( I mean=0A> > exported by the kernel or ACPI driver ) and How do I know = at what=0A> > frequency is my CPU running?=0A> >=0A> > Any pointers to any = utilities/resources will be of great help.=0A> >=0A> > Regards,=0A> > Sreen= idhi,=0A> >=0A> >=0A> >=0A> > ---=0A> > Nachricht wurde webbasiert erstellt= ,=0A> > Angaben ueber Absender sind nicht verifiziert.=0A --Next_1094639576---0-203.199.83.27-4432-- ------------------------------------------------------- This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! 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