From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: Overall picture of cpufreq.. Date: Mon, 14 Jan 2008 11:59:35 +0100 Message-ID: <478B4097.8010401@wpkg.org> References: <9f79f7f50801111415w354dc91fwfeec98b16a00fb74@mail.gmail.com> <1200264884.4157.16.camel@queen> <9f79f7f50801131812x6a68c202tb4c25fa2116b32e4@mail.gmail.com> <478B0A82.6050503@wpkg.org> <1200304310.23376.311.camel@queen.suse.de> <478B3695.1030406@wpkg.org> <1200306768.23376.332.camel@queen.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1200306768.23376.332.camel@queen.suse.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk To: trenn@suse.de Cc: Martin.Leisner@xerox.com, cpufreq@lists.linux.org.uk Thomas Renninger schrieb: (...) >>> could it be that you are using >>> p4-clockmode driver which is doing throttling, not frequency scaling, >>> better try with acpi-cpufreq then. >> Indeed, I am using p4-clockmod. > Sorry, but your bug report is invalid then. > p4-clockmod is using throttling (means the CPU ignores cycles/ticks) and > not CPU frequency/voltage reduction. > There is another interface for that: > /proc/acpi/processor/throttling Umm, do I need to build/insert some additional modules here? # cat /proc/acpi/processor/CPU0/throttling (...) >> acpi-cpufreq doesn't work for me on that machine (p4-clockmod not loaded >> when I try to insert acpi-cpufreq): >> >> # modprobe acpi-cpufreq >> FATAL: Error inserting acpi_cpufreq >> (/lib/modules/2.6.23.12-pata-1/kernel/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.ko): >> No such device > > Have you checked whether that the CPU is cpufreq capable at all? According to Documentation/cpu-freq/user-guide.txt, Intel Xeon is supported by cpufreq. Are there exceptions to that (i.e., some Xeons are not supported)? Anyway, "cat /dev/zero >/dev/null" scales the frequency up; reading from a dm-crypt device doesn't. > If yes, you might want to upgrade the BIOS. > > Still, it looks strange that frequency (in this case throttling) is not > set to the highest state as measuring the idle time should be the same > mechanism and low-level driver independent. So this may be a valid bug, > but using p4-clockmode is not a good idea to work on it (p4-clockmode is > not a good idea to work on in general, IMO it should vanish totally...). In that case, it's not documented very clearly (in "make menuconfig"). Basically, a P4 user can pick either: CONFIG_X86_ACPI_CPUFREQ: This driver adds a CPUFreq driver which utilizes the ACPI Processor Performance States. This driver also supports Intel Enhanced Speedstep. or: CONFIG_X86_P4_CLOCKMOD: This adds the CPUFreq driver for Intel Pentium 4 / XEON processors. CONFIG_X86_P4_CLOCKMOD is more explicit and implies that is the preferred module for a P4 CPU. -- Tomasz Chmielewski http://wpkg.org